CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (unaudited) (Parenthetical) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Tax expense (benefit) on cash flow hedges reclassified from AOCI to net income	$ 2	$ 1	$ 5	$ 4
Tax expense (benefit) of unrealized gains/losses on available for sale securities still held	(1)	19	(3)	45
Tax expense (benefit) on available for sale securities reclassified from AOCI to net income	1	(1)	(1)	(11)
Tax expense (benefit) of defined benefit pension and other benefits plans	(1)	6	(1)	4
Tax expense (benefit) of foreign currency translation	0	1	0	1
Tax expense (benefit) of other comprehensive income (loss) related to equity method investees	(1)	(1)	1	0
AOCI Impacts of NEP Deconsolidation, tax	$ 0	$ 0	$ 15	$ 0