Condensed Financial Information Condensed Statement of Comprehensive Income (Loss) (Parent Only) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Condensed Financial Statements, Captions [Line Items]
Other revenue									$ 43	$ 41	$ 39
Total net revenue	$ 637	$ 599	$ 577	$ 553	$ 509	$ 486	$ 474	$ 472	2,366	1,941	1,370
Total non-interest expense									1,470	1,252	1,319
Income before income tax expense (benefit) and equity in income (loss) of consolidated subsidiaries									1,064	838	91
Income tax expense (benefit)									450	286	(177)
Net income	$ 129	$ 147	$ 193	$ 145	$ 127	$ 139	$ 133	$ 153	614	552	268
Other comprehensive (loss) income									111	(38)	150
Comprehensive income									725	514	418
Net income available to common shareholders									589	552	268
Preferred stock dividends									25	0	0
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Dividends from subsidiaries(1)									350	858	859
Other revenue									377	328	317
Total net revenue									727	1,186	1,176
Total non-interest expense									611	501	560
Income before income tax expense (benefit) and equity in income (loss) of consolidated subsidiaries									116	685	616
Income tax expense (benefit)									75	456	(287)
Equity in undistributed income (loss) of subsidiaries									573	323	(635)
Net income									614	552	268
Other comprehensive (loss) income									111	(38)	150
Comprehensive income									725	514	418
Net income available to common shareholders									589
Preferred stock dividends									$ 25
E TRADE Bank [Member]
Condensed Financial Statements, Captions [Line Items]
Dividends from subsidiaries(1)										$ 423	$ 281