Accumulated Other Comprehensive Income (Loss) Before and After Tax (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Tax, [Abstract]
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, before Tax	$ 138	$ 188
Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, before Tax	55	43
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Tax, Portion Attributable to Parent	83	145
Other Comprehensive Income (Loss), Available-for-sale Securities, Tax [Abstract]
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Tax	(51)	(51)
Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, Tax	(20)	(6)
Other Comprehensive Income (Loss), Available-for-sale Securities, Tax, Portion Attributable to Parent	(31)	(45)
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax [Abstract]
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax	87	137
Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, Net of Tax	35	37
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax, Portion Attributable to Parent	52	100
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax [Abstract]
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax	(20)	(22)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment Realized upon Sale or Liquidation, before Tax	42
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax, Portion Attributable to Parent	(62)
Other Comprehensive Income Unrealized Gain Loss On Net Investment Hedges Arising During the Period, Before Tax	18	11
Other Comprehensive Income (Loss), Reclassification Adjustment for Net Investment Hedges Included in Net Income, Discontinued Operation, before Tax	(4)
Other Comprehensive Income (Loss), Net Investment Hedges Attributable to Parent, before Tax	22
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax [Abstract]
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax	7	7
Other Comprehensive Income (Loss), Foreign Currency Translation Reclassification Adjustment Realized upon Sale or Liquidation, Tax	(20)
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax, Portion Attributable to Parent	27
Other Comprehensive Income Unrealized Gain Loss On Net Investment Hedges Arising During the Period, Tax	(7)	(4)
Other Comprehensive Income (Loss), Reclassification Adjustment for Net Investment Hedges Included in Net Income, Discontinued Operation, Tax	1
Other Comprehensive Income (Loss), Net Investment Hedges Attributable to Parent, Tax	(8)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax [Abstract]
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax	(13)	(15)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment Realized upon Sale or Liquidation, Net of Tax	22
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Parent	(35)
Other Comprehensive Income Unrealized Gain Loss On Net Investment Hedges Arising During the Period Net of Tax	11	7
Other Comprehensive Income (Loss), Reclassification Adjustment for Net Investment Hedges Included in Net Income, Discontinued Operation, Net of Tax	(3)
Other Comprehensive Income (Loss), Net Investment Hedges Attributable to Parent, Net of Tax	14
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent	43	134
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	(12)	(42)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	$ 31	$ 92