Equity - Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	$ 22,748	$ 19,534
Other comprehensive income/(loss)	(25)	8
Ending balance	22,703	19,994
Accumulated other comprehensive loss
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(196)	(192)
Other comprehensive income/(loss)	(25)	8
Income tax benefit (expense)	0	0
Other comprehensive income/(loss)	(25)	8
Ending balance	(221)	(184)
Foreign currency translation adjustments
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(150)	(134)
Other comprehensive income/(loss)	(25)	6
Income tax benefit (expense)	0	1
Other comprehensive income/(loss)	(25)	7
Ending balance	(175)	(127)
Comprehensive income from equity method investment
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	2	1
Other comprehensive income/(loss)	0	2
Income tax benefit (expense)	0	(1)
Other comprehensive income/(loss)	0	1
Ending balance	2	2
Employee benefit plans adjustments
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(48)	(59)
Other comprehensive income/(loss)	0	0
Income tax benefit (expense)	0	0
Other comprehensive income/(loss)	0	0
Ending balance	$ (48)	$ (59)