Shareholders' Equity - Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period			$ 181
Balance at end of period	$ 272		272
Other comprehensive income (loss) attributable to noncontrolling interests	4	$ 7	(2)	$ (13)
Accumulated Other Comprehensive Income (Loss)
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	(789)	(908)	(744)	(711)
Balance at end of period	(729)	(874)	(729)	(874)
Foreign currency translation adjustments:
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	(441)	(568)	(395)	(369)
Other comprehensive income (loss) before reclassifications	58	34	12	(165)
Reclassification from other comprehensive income (loss)	0	0	0	0
Other comprehensive income (loss)	58	34	12	(165)
Income tax benefit (provision)	0	1	0	1
Balance at end of period	(383)	(533)	(383)	(533)
Defined benefit plans:
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	(350)	(338)	(353)	(342)
Other comprehensive income (loss) before reclassifications	0	0	0	0
Reclassification from other comprehensive income (loss)	3	1	7	4
Other comprehensive income (loss)	3	1	7	4
Income tax benefit (provision)	0	(6)	(1)	(5)
Balance at end of period	(347)	(343)	(347)	(343)
Cash flow hedges:
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	2	(2)	4	0
Other comprehensive income (loss) before reclassifications	(1)	5	1	2
Reclassification from other comprehensive income (loss)	0	0	(4)	0
Other comprehensive income (loss)	(1)	5	(3)	2
Income tax benefit (provision)	0	(1)	0	0
Balance at end of period	$ 1	$ 2	$ 1	$ 2