Accumulated Other Comprehensive Income (Loss) - Summary of AOCI(L) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Changes in Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	$ 2,284	$ 3,200	$ 3,030	$ 3,258
Other comprehensive income (loss)	74	(55)	(204)	(20)
Ending balance	2,358	3,095	2,358	3,095
Accumulated Other Comprehensive Income Attributable to Parent
Changes in Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	(1,983)	(1,642)	(1,705)	(1,677)
Ending balance	(1,909)	(1,697)	(1,909)	(1,697)
Accumulated Foreign Currency Adjustment Attributable to Parent
Changes in Accumulated Other Comprehensive Income [Roll Forward]
Other comprehensive income (loss), adjustments during the period	47	(76)	(225)	(33)
Income taxes	17	16	2	4
Other comprehensive income (loss)	64	(60)	(223)	(29)
Accumulated Defined Benefit Plans Adjustment Attributable to Parent
Changes in Accumulated Other Comprehensive Income [Roll Forward]
Other comprehensive income (loss), adjustments reclassified to income	12	6	24	11
Income taxes	(2)	(1)	(5)	(2)
Other comprehensive income (loss)	$ 10	$ 5	$ 19	$ 9