Changes In Accumulated Other Comprehensive (Loss) Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Changes in other comprehensive income
Balances as of start of period	$ (1,188)	$ (941)	$ (1,156)	$ (787)
Net translation gain (loss) of investment in foreign operations	30	(376)	(3)	(616)
Net gains (losses) related to hedges of investment in foreign operations	(29)	188	(28)	274
Net change in accumulated other comprehensive loss	1	(188)	(31)	(342)
Balances as of end of period	$ (1,187)	$ (1,129)	$ (1,187)	$ (1,129)