Statements of Consolidated Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 29.1	$ 28.0
Other comprehensive (loss) income, net of tax:
Defined benefit pension plan and Salaried VEBA	1.1	1.1
Available for sale securities	(0.2)	(0.2)
Cash flow hedges	(15.9)	8.8
Fair value hedges	(0.5)	0.0
Other comprehensive (loss) income, net of tax	(15.5)	9.7
Comprehensive income	$ 13.6	$ 37.7

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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