CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Statement of Comprehensive Income [Abstract]
Change in unrealized holding gains (losses) on available-for-sale securities, tax (expense) benefit	$ (37)	$ 105	$ (80)	$ 111
Reclassification adjustment for gross gains included in net income, tax benefit	$ 2	$ 2	$ 7	$ 7