Credit Losses - Rollforward of Allowances (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at Beginning of Year	$ 220.1	$ 140.0
Provision for credit losses	75.7	102.9
Provision for credit losses deferred for future recovery or refund	(13.1)	55.2
Write-offs charged against the allowance	(129.8)	(132.3)
Recovery of amounts previously written off	45.4	54.4
Sale of PDL residential solar facilities		(0.1)
Balance at End of Year	198.3	220.1
Public Utilities
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at Beginning of Year	220.1	139.9
Provision for credit losses	75.7	102.9
Provision for credit losses deferred for future recovery or refund	(13.1)	55.2
Write-offs charged against the allowance	(129.8)	(132.3)
Recovery of amounts previously written off	45.4	54.4
Sale of PDL residential solar facilities		0.0
Balance at End of Year	198.3	220.1
Wisconsin | Public Utilities
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at Beginning of Year	102.1	59.9
Provision for credit losses	46.4	47.5
Provision for credit losses deferred for future recovery or refund	(16.6)	24.6
Write-offs charged against the allowance	(74.8)	(65.9)
Recovery of amounts previously written off	26.9	36.0
Sale of PDL residential solar facilities		0.0
Balance at End of Year	84.0	102.1
Illinois | Public Utilities
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at Beginning of Year	111.6	75.9
Provision for credit losses	25.6	51.1
Provision for credit losses deferred for future recovery or refund	3.5	30.6
Write-offs charged against the allowance	(52.5)	(63.0)
Recovery of amounts previously written off	17.3	17.0
Sale of PDL residential solar facilities		0.0
Balance at End of Year	105.5	111.6
Other States | Public Utilities
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at Beginning of Year	6.4	4.1
Provision for credit losses	3.7	4.3
Provision for credit losses deferred for future recovery or refund	0.0	0.0
Write-offs charged against the allowance	(2.5)	(3.4)
Recovery of amounts previously written off	1.2	1.4
Sale of PDL residential solar facilities		0.0
Balance at End of Year	8.8	6.4
Corporate and Other
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at Beginning of Year	0.0	0.1
Provision for credit losses	0.0	0.0
Provision for credit losses deferred for future recovery or refund	0.0	0.0
Write-offs charged against the allowance	0.0	0.0
Recovery of amounts previously written off	0.0	0.0
Balance at End of Year	$ 0.0	0.0
Corporate and Other | WPS Power Development, LLC Residential Solar Facilities
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Sale of PDL residential solar facilities		$ (0.1)