Annual report pursuant to Section 13 and 15(d)

Debt (Details)

v3.22.4
Debt (Details) - USD ($)
$ in Millions
 3 Months Ended 12 Months Ended
Mar. 22, 2022
Mar. 04, 2019
Dec. 31, 2022
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Oct. 02, 2021
Jul. 16, 2021
Dec. 31, 2019
Jul. 03, 2019
Long-term Debt [Abstract]                    
Total Long-Term Debt Including Current Maturities     $ 2,544.7 $ 2,544.7 $ 1,845.2          
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net     (35.7) (35.7) (28.8)          
Other Long-term Debt     13.9 13.9 7.4          
Current Maturities of Long-term Debt     (89.0) (89.0) (37.4)          
Long-Term Debt, Net     2,420.0 2,420.0 1,779.0          
Proceeds from Issuance of Long-term Debt, Current and Long-term       749.0            
Maturities of Long-term Debt [Abstract]                    
2019     89.0 89.0            
2020     451.5 451.5            
2021     1.3 1.3            
2022     1.1 1.1            
2023     161.3 161.3            
Thereafter     1,840.5 1,840.5            
Total Long-Term Debt Including Current Maturities     2,544.7 2,544.7 1,845.2          
Line of Credit Facility [Abstract]                    
Letters of Credit Outstanding, Amount     3.4 3.4            
Proceeds from Issuance of Commercial Paper       500.0 200.0          
Commercial Paper, Maximum Amount Utilized       300.0 100.0          
Proceeds from Notes Payable $ 741.8     992.9            
Less: Restricted Cash     12.9 12.9 12.2 $ 10.7        
Proceeds from Issuance of Long-term Debt, Excluding Current Maturities       741.8            
Repayments of Long-term Debt, Current       (37.3)            
Repayments of Long-term Debt, Current and Long-term       (59.1)            
Other Debt Activity, Excluding Current Maturities       2.6            
Other Debt Activity, Current       0.1            
Other Debt Activity, Current and Long-term       2.7            
Debt, Long-term and Short-term, Combined Amount     2,509.0 2,509.0 1,816.4          
Proceeds from Issuance of Long-term Debt, Current       7.2            
Repayments of Long-term Debt, Excluding Current Maturities       (21.8)            
Short-Term Debt, Refinanced, Amount       (81.6)            
Reclassification of total debt       0.0            
Payments of Debt Issuance Costs       8.2 7.1          
Transaction Financing Charges       0.1 4.2 0.0        
Line of Credit Facility, Maximum Amount Outstanding During Period     127.8              
Commercial Paper, Maximum Amount Allowed to be Utilized       500.0            
SEC Schedule, 12-09, Valuation Allowance, Deferred Tax Asset [Member]                    
Line of Credit Facility [Abstract]                    
SEC Schedule, 12-09, Valuation Allowances and Reserves, Amount     52.8 52.8 97.9 93.4     $ 93.3  
Recoveries       0.0 0.0 0.0        
Trustee Bank [Domain]                    
Line of Credit Facility [Abstract]                    
Less: Restricted Cash     8.0 8.0 12.2          
Total Pension Plan Net Assets [Member] | Fair Value, Inputs, Level 3 [Member]                    
Line of Credit Facility [Abstract]                    
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount     0.0 0.0            
Nonqualified Plan [Member]                    
Line of Credit Facility [Abstract]                    
Defined Benefit Plan, Pension Plan with Projected Benefit Obligation in Excess of Plan Assets, Accumulated Benefit Obligation     0.0 $ 0.0 0.0          
Commercial Paper [Member]                    
Line of Credit Facility [Abstract]                    
Line of Credit Facility, Maximum Borrowing Capacity             $ 300.0      
Maximum [Member]                    
Line of Credit Facility [Abstract]                    
Debt Instrument, Covenant, Leverage Ratio       3.50            
Minimum [Member]                    
Line of Credit Facility [Abstract]                    
Debt Instrument, Covenant, Interest Coverage Ratio       3.00            
6.375% Senior Notes due 2049 [Member]                    
Long-term Debt [Abstract]                    
Total Long-Term Debt Including Current Maturities     230.0 $ 230.0 230.0          
Maturities of Long-term Debt [Abstract]                    
Total Long-Term Debt Including Current Maturities     230.0 $ 230.0 230.0          
Senior Notes Due 2021 [Member]                    
Line of Credit Facility [Abstract]                    
Debt Instrument, Redemption Price, Triggering Event       101.00%            
Debentures Due 2023 [Member]                    
Long-term Debt [Abstract]                    
Total Long-Term Debt Including Current Maturities     80.1 [1] $ 80.1 [1] 80.8          
Maturities of Long-term Debt [Abstract]                    
Total Long-Term Debt Including Current Maturities     $ 80.1 [1] $ 80.1 [1] $ 80.8          
Loan With Fond Du Lac County Economic Development Corporation Due 2021 [Member]                    
Long-term Debt [Abstract]                    
Interest Rate     7.375% 7.375% 7.375%          
Line of Credit Facility [Abstract]                    
Total Loan Forgiveness         $ 2.1 $ 2.1        
Annual Forgiveness Percent         43.00% 43.00%        
Notes Due 2027 [Member]                    
Long-term Debt [Abstract]                    
Total Long-Term Debt Including Current Maturities     $ 160.7 $ 160.7 $ 160.7          
Maturities of Long-term Debt [Abstract]                    
Total Long-Term Debt Including Current Maturities     160.7 $ 160.7 160.7          
Senior Notes Due 2048 [Member] [Member]                    
Line of Credit Facility [Abstract]                    
Debt Instrument, Redemption Price, Triggering Event       101.00%            
Term Loan Due 2023 [Member]                    
Long-term Debt [Abstract]                    
Total Long-Term Debt Including Current Maturities [2],[3]     $ 0.0 $ 0.0 56.3          
Interest Rate     1.72% 1.72%            
Maturities of Long-term Debt [Abstract]                    
Total Long-Term Debt Including Current Maturities [2],[3]     $ 0.0 $ 0.0 56.3          
6.625% Senior Notes due 2049 [Member]                    
Long-term Debt [Abstract]                    
Total Long-Term Debt Including Current Maturities     125.0 125.0 125.0          
Maturities of Long-term Debt [Abstract]                    
Total Long-Term Debt Including Current Maturities     125.0 125.0 125.0          
6.500% Senior Notes due 2048 [Member]                    
Long-term Debt [Abstract]                    
Total Long-Term Debt Including Current Maturities     185.0 185.0 185.0          
Maturities of Long-term Debt [Abstract]                    
Total Long-Term Debt Including Current Maturities     185.0 185.0 185.0          
Senior Notes, 2.4% due 2031                    
Long-term Debt [Abstract]                    
Total Long-Term Debt Including Current Maturities     550.0 550.0 550.0          
Maturities of Long-term Debt [Abstract]                    
Total Long-Term Debt Including Current Maturities     550.0 550.0 550.0          
0.85% Senior Note Due 2024                    
Long-term Debt [Abstract]                    
Total Long-Term Debt Including Current Maturities     450.0 450.0 450.0          
Maturities of Long-term Debt [Abstract]                    
Total Long-Term Debt Including Current Maturities     450.0 450.0 450.0          
5.100% Senior Notes due 2052                    
Long-term Debt [Abstract]                    
Total Long-Term Debt Including Current Maturities     300.0 300.0 0.0          
Maturities of Long-term Debt [Abstract]                    
Total Long-Term Debt Including Current Maturities     300.0 300.0 0.0          
4.400% Senior Notes due 2032                    
Long-term Debt [Abstract]                    
Total Long-Term Debt Including Current Maturities     450.0 450.0 0.0          
Maturities of Long-term Debt [Abstract]                    
Total Long-Term Debt Including Current Maturities     450.0 450.0 $ 0.0          
Line of Credit [Member]                    
Line of Credit Facility [Abstract]                    
Line of Credit Facility, Maximum Borrowing Capacity               $ 750.0    
Line of Credit Facility, Remaining Borrowing Capacity     747.2 747.2            
Letters of Credit Outstanding, Amount     2.8 2.8            
Line of Credit Facility, Increase (Decrease), Other, Net       $ 100.0            
Line of Credit Facility, Commitment Fee Percentage       0.15%            
Line of Credit Facility, Current Borrowing Capacity     125.0 $ 125.0            
Line of Credit [Member] | Maximum [Member]                    
Line of Credit Facility [Abstract]                    
Line of Credit Facility, Commitment Fee Percentage       0.35%            
Line of Credit [Member] | Minimum [Member]                    
Line of Credit Facility [Abstract]                    
Line of Credit Facility, Commitment Fee Percentage       0.125%            
Line of Credit [Member] | London Interbank Offered Rate (LIBOR) [Member]                    
Line of Credit Facility [Abstract]                    
Line of Credit Facility, Interest Rate During Period       1.10%            
Line of Credit [Member] | London Interbank Offered Rate (LIBOR) [Member] | Maximum [Member]                    
Line of Credit Facility [Abstract]                    
Line of Credit Facility, Interest Rate During Period       1.90%            
Line of Credit [Member] | London Interbank Offered Rate (LIBOR) [Member] | Minimum [Member]                    
Line of Credit Facility [Abstract]                    
Line of Credit Facility, Interest Rate During Period       1.00%            
Line of Credit [Member] | Base Rate [Member]                    
Line of Credit Facility [Abstract]                    
Line of Credit Facility, Interest Rate During Period       0.10%            
Line of Credit [Member] | Base Rate [Member] | Maximum [Member]                    
Line of Credit Facility [Abstract]                    
Line of Credit Facility, Interest Rate During Period       0.90%            
Line of Credit [Member] | Base Rate [Member] | Minimum [Member]                    
Line of Credit Facility [Abstract]                    
Line of Credit Facility, Interest Rate During Period       0.00%            
Senior Notes Due 2021 [Member] | Unsecured Debt [Member]                    
Line of Credit Facility [Abstract]                    
Senior Notes                   $ 150.0
6.375% Senior Notes due 2049 [Member]                    
Line of Credit Facility [Abstract]                    
Debt Instrument, Redemption Price, Triggering Event       101.00%            
6.625% Senior Notes due 2049 [Member]                    
Line of Credit Facility [Abstract]                    
Debt Instrument, Redemption Price, Triggering Event       101.00%            
Senior Notes Due 2049 [Member] | Unsecured Debt [Member]                    
Line of Credit Facility [Abstract]                    
Debt Instrument, Face Amount   $ 230.0                
Proceeds from Issuance of Debt   $ 222.0                
Term Loan Due 2023 [Member] | Unsecured Debt [Member]                    
Line of Credit Facility [Abstract]                    
Repayments of Other Debt       $ 95.0            
0.850% Senior Notes due 2024                    
Line of Credit Facility [Abstract]                    
Senior Notes     450.0 450.0            
2,400% Senior Notes due 2031                    
Line of Credit Facility [Abstract]                    
Senior Notes     550.0 550.0            
Debentures Due 2023 [Member]                    
Line of Credit Facility [Abstract]                    
Debt Instrument, Face Amount     103.1 103.1            
Debt Instrument, Repurchase Amount     23.4 23.4            
Notes Due 2027 [Member]                    
Line of Credit Facility [Abstract]                    
Debt Instrument, Repurchase Amount     $ 2.5 $ 2.5            
4.400% Senior Notes due 2032                    
Line of Credit Facility [Abstract]                    
Senior Notes 450.0                  
5.100% Senior Notes due 2052                    
Line of Credit Facility [Abstract]                    
Senior Notes $ 300.0                  
[1] (A) Included in Debentures, 7.375% due 2023 as of December 31, 2022 and December 31, 2021, are the aggregate fair values related to the fixed-to-floating interest rate swaps as discussed in Note 13 – Financial Instruments. During the third quarter of 2022, the Debentures were reclassified from Long-term debt to Current maturities of long-term debt.
[2] (B) During 2022, the Company made the remaining principal repayments, totaling $56.3 million.
[3] As of December 31, 2021, the interest rate was 1.72%.