Shareholders' Equity - Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 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	$ 223		223
Other comprehensive income (loss) attributable to noncontrolling interests	(5)	$ 10	(7)	$ (3)
Accumulated Other Comprehensive Income (Loss)
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	(729)	(874)	(744)	(711)
Balance at end of period	(801)	(854)	(801)	(854)
Foreign currency translation adjustments:
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	(383)	(533)	(395)	(369)
Other comprehensive income (loss) before reclassifications	(74)	33	(62)	(132)
Reclassification from other comprehensive income (loss)	0	0	0	0
Other comprehensive income (loss)	(74)	33	(62)	(132)
Income tax benefit (provision)	0	0	0	1
Balance at end of period	(457)	(500)	(457)	(500)
Defined benefit plans:
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	(347)	(343)	(353)	(342)
Other comprehensive income (loss) before reclassifications	0	0	0	0
Reclassification from other comprehensive income (loss)	3	(14)	10	(10)
Other comprehensive income (loss)	3	(14)	10	(10)
Income tax benefit (provision)	0	0	(1)	(5)
Balance at end of period	(344)	(357)	(344)	(357)
Cash flow hedges:
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	1	2	4	0
Other comprehensive income (loss) before reclassifications	0	1	1	3
Reclassification from other comprehensive income (loss)	(1)	0	(5)	0
Other comprehensive income (loss)	(1)	1	(4)	3
Income tax benefit (provision)	0	0	0	0
Balance at end of period	$ 0	$ 3	$ 0	$ 3