INCOME TAXES (Tables)

6 Months Ended

Jun. 30, 2020

Income Tax Disclosure [Abstract]

Schedule of effective income tax rate reconciliation

The provision for income taxes differs from the amount of income tax determined by applying the applicable United States statutory federal income tax rate to income before income taxes as a result of the following:

	Three Months Ended June 30, 2020				Three Months Ended June 30, 2019
(in millions)	Amount		Effective Tax Rate		Amount		Effective Tax Rate
Statutory federal income tax	$	62.2	21.0	%	$	52.7	21.0	%
State income taxes net of federal tax benefit	18.4		6.2	%	15.6		6.2	%
Federal excess deferred tax amortization – Wisconsin unprotected	(11.1)		(3.8)	%	—		—	%
Wind production tax credits	(9.4)		(3.2)	%	(6.2)		(2.5)	%
Federal excess deferred tax amortization	(8.9)		(3.0)	%	(7.5)		(3.0)	%
Excess tax benefits – stock options	(1.4)		(0.5)	%	(4.4)		(1.7)	%
Tax repairs	—		—	%	(30.4)		(12.1)	%
Other	4.0		1.5	%	(4.6)		(1.8)	%
Total income tax expense	$	53.8	18.2	%	$	15.2	6.1	%

	Six Months Ended June 30, 2020				Six Months Ended June 30, 2019
(in millions)	Amount		Effective Tax Rate		Amount		Effective Tax Rate
Statutory federal income tax	$	176.1	21.0	%	$	154.6	21.0	%
State income taxes net of federal tax benefit	52.4		6.3	%	46.5		6.3	%
Federal excess deferred tax amortization – Wisconsin unprotected	(33.2)		(4.0)	%	—		—	%
Wind production tax credits	(27.8)		(3.3)	%	(19.6)		(2.7)	%
Federal excess deferred tax amortization	(21.9)		(2.6)	%	(20.7)		(2.8)	%
Excess tax benefits – stock options	(6.3)		(0.8)	%	(11.6)		(1.6)	%
Tax repairs	1.5		0.2	%	(60.0)		(8.1)	%
Other	3.0		0.3	%	(9.0)		(1.2)	%
Total income tax expense	$	143.8	17.1	%	$	80.2	10.9	%