CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Statement of Comprehensive Income [Abstract]
Change in unrealized holding (losses) gains on available-for-sale securities, tax benefit (expense)	$ 73	$ (37)	$ 45	$ (80)
Reclassification adjustment for gross gains included in net income, tax benefit	$ 2	$ 2	$ 4	$ 7