CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statement of Comprehensive Income [Abstract]
Change in unrealized holding (losses) gains on available-for-sale securities, tax benefit (expense)	$ 22	$ 32	$ 66	$ (48)
Reclassification adjustment for gross losses (gains) included in net income, tax (expense) benefit	$ 0	$ 1	$ 4	$ 8