CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Tax expense (benefit) on cash flow hedges reclassified from AOCI to net income	$ 3	$ 3
Tax expense (benefit) of unrealized gains/losses on available for sale securities still held	3	(2)
Tax expense (benefit) on available for sale securities reclassified from AOCI to net income	1	(2)
Tax expense (benefit) of defined benefit pension and other benefits plans	(16)	(1)
Tax expense (benefit) of defined benefit pension and other benefits plans reclassified from AOCI to net income	(1)	(1)
Tax expense (benefit) of other comprehensive income (loss) related to equity method investees	(1)	1
AOCI Impacts of NEP Deconsolidation, tax	$ 0	$ 15