Consolidated Statement of Comprehensive Income (Parenthetical) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Other Comprehensive Income (Loss), Available-for-sale Securities, Tax	$ (738)	$ 199	$ 213
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax Effect	(25)	22	65
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, Tax	$ (35)	$ (141)	$ 46