Accumulated Other Comprehensive (Loss) Income (Rollforward) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax [Abstract]
Beginning Balance Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax			$ (159)	$ (21)
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax, Portion Attributable to Parent	$ (4)	$ 62	258	(35)
Ending Balance Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	99	(56)	99	(56)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax [Abstract]
Beginning Balance Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax			9	36
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax			5	(21)
Ending Balance Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax	14	15	14	15
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax [Abstract]
Beginning Balance Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax			8	7
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax, Portion Attributable to Parent			0	0
Ending Balance Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax	8	7	8	7
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax [Abstract]
Beginning Balance Accumulated Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net of Tax			(89)	(88)
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax, Portion Attributable to Parent			(1)	0
Ending Balance Accumulated Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net of Tax	(90)	(88)	(90)	(88)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated Other Comprehensive Income (Loss), Net of Tax			(231)	(66)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(4)	61	262	(56)
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ 31	$ (122)	$ 31	$ (122)