Consolidated Statement of Shareholder's Interest - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ 14,894	$ 14,923	$ 15,350	$ 15,685	$ 14,894	$ 15,350
Shareholder's Interest [Roll Forward]
Balance at beginning of period		5,227			5,227
Net income	613	603	479	701	1,216	1,180
Other Comprehensive Income (Loss), Net of Tax	8	20	(364)	113
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	8		(364)		28	(251)
Distributions declared	(650)	(675)	(450)	(1,013)
Balance at end of period	5,227				5,227
Shareholder's Interest [Member]
Shareholder's Interest [Roll Forward]
Balance at beginning of period	5,227	5,227	5,227	5,227	5,227	5,227
Net income	0	0	0	0
Other Comprehensive Income (Loss), Net of Tax	0	0	0	0
Distributions declared	0	0	0	0
Balance at end of period	5,227	5,227	5,227	5,227	5,227	5,227
Accumulated Other Comprehensive Income/(Loss) (Note11) [Member]
Shareholder's Interest [Roll Forward]
Balance at beginning of period	(809)	(829)	(306)	(419)	(829)	(419)
Net income	0	0	0	0
Other Comprehensive Income (Loss), Net of Tax	8	20		113
Distributions declared	0	0	0	0
Balance at end of period	(801)	(809)	(670)	(306)	(801)	(670)
Retained Earnings [Member]
Shareholder's Interest [Roll Forward]
Balance at beginning of period	10,505	10,577	10,764	11,076	10,577	11,076
Net income	613	603		701
Other Comprehensive Income (Loss), Net of Tax	0	0	0	0
Distributions declared	(650)	(675)	(450)	(1,013)
Balance at end of period	$ 10,468	$ 10,505	$ 10,793	$ 10,764	$ 10,468	$ 10,793