Income Tax Expense (Tables)

9 Months Ended

Sep. 30, 2018

Income Tax Disclosure [Abstract]

Income Tax Expense [Table Text Block]

	Quarter Ended						Nine Months Ended
	September 30,						September 30,
	2018			2017			2018			2017
Millions
Current Income Tax Expense (a)
Federal	—			—			—			—
State	—				$0.1			$0.4			$0.3
Total Current Income Tax Expense	—				$0.1			$0.4			$0.3
Deferred Income Tax Expense (Benefit)
Federal (b)	$(2.2)				$9.2		$(16.4)				$20.3
State	2.8			5.0			7.8			14.5
Investment Tax Credit Amortization	(0.2		)	(0.1		)	(0.5		)	(0.5		)
Total Deferred Income Tax Expense (Benefit)		$0.4			$14.1		$(9.1)				$34.3
Total Income Tax Expense (Benefit)		$0.4			$14.2		$(8.7)				$34.6

(a) For the quarter and nine months ended September 30, 2018, and 2017, the federal and state current tax expense was minimal due to NOLs which resulted from the bonus depreciation provisions of the Protecting Americans from Tax Hikes Act of 2015, the Tax Increase Prevention Act of 2014 and the American Taxpayer Relief Act of 2012.

(b) For the quarter and nine months ended September 30, 2018, the federal tax benefit is primarily due to the reduction of the federal statutory tax rate from 35 percent to 21 percent enacted as part of the TCJA and production tax credits.

Reconciliation of Taxes from Federal Statutory Rate to Total Income Tax Expense [Table Text Block]

	Quarter Ended						Nine Months Ended
Reconciliation of Taxes from Federal Statutory	September 30,						September 30,
Rate to Total Income Tax Expense	2018			2017			2018			2017
Millions
Income Before Non-Controlling Interest and Income Taxes		$31.1			$59.1			$104.3			$165.4
Statutory Federal Income Tax Rate	21		%	35		%	21		%	35		%
Income Taxes Computed at Statutory Federal Rate		$6.5			$20.7			$21.9			$57.9
Increase (Decrease) in Income Tax Due to:
State Income Taxes – Net of Federal Income Tax Benefit	2.2			3.3			6.4			9.6
Production Tax Credits	(9.4		)	(10.4		)	(35.0		)	(33.4		)
Regulatory Differences – Excess Deferred Tax	(1.1		)	0.3			(5.5		)	1.0
Other	2.2			0.3			3.5			(0.5		)
Total Income Tax Expense (Benefit)		$0.4			$14.2		$(8.7)				$34.6