CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Statement of Comprehensive Income [Abstract]
Change in unrealized holding (losses) gains on available-for-sale securities, tax benefit (expense)	$ 32	$ 12	$ (48)	$ 123
Reclassification adjustment for gross (gains) losses included in net income, tax benefit (expense)	$ 1	$ (12)	$ 8	$ (5)