Consolidated Statement of Comprehensive Income Statement - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Net Income (Loss) Attributable to Parent	$ 929	$ 1,067	$ 1,289
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	192	33	(39)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax	92	147	99
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	100	(114)	(138)
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 before reclassification adjustments, Net of Tax	8	3	(26)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, Net of Tax	0	(1)	22
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax	8	4	(48)
Other Comprehensive Income Unrealized Gain Loss On Net Investment Hedges Arising During the Period Net of Tax	(6)	1	18
Other Comprehensive Income (Loss), Reclassification Adjustment for Net Investment Hedges Included in Net Income, Discontinued Operation, Net of Tax	0	0	(3)
Other Comprehensive Income (Loss), Net Investment Hedges, Net of Tax	(6)	1	21
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustments and Net Investment Hedges, Net of Tax	2	5	(27)
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax [Abstract]
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	3	0	1
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax [Abstract]
Other Comprehensive (Income) Loss, Defined Benefit Plan, before Reclassification Adjustment, after Tax	1	(3)	0
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, after Tax	0	(2)	1
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	(1)	1	1
Other Comprehensive Income (Loss), Net of Tax	106	(110)	(165)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	1,035	957	1,124
Retained Earnings [Member]
Net Income (Loss) Attributable to Parent	$ 929	$ 1,067	$ 1,289