Accumulated Other Comprehensive Income (Loss) (AOCI) Changes in Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification		$ 1
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated other comprehensive income (loss), beginning balance	$ (246)	(199)	$ (205)
Other comprehensive (loss) income before reclassifications	(11)	(34)	15
Amounts reclassified from AOCI	(12)	(14)	(9)
Net current period other comprehensive (loss) income	(23)	(48)	6
Accumulated other comprehensive income (loss), ending balance	(269)	(246)	(199)
Currency Translation Adjustments
Accumulated Other Comprehensive Income [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification		0
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated other comprehensive income (loss), beginning balance	(234)	(183)	(224)
Other comprehensive (loss) income before reclassifications	(26)	(51)	41
Amounts reclassified from AOCI	0	0	0
Net current period other comprehensive (loss) income	(26)	(51)	41
Accumulated other comprehensive income (loss), ending balance	(260)	(234)	(183)
Changes in Employee Benefit Plans
Accumulated Other Comprehensive Income [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification		1
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated other comprehensive income (loss), beginning balance	(14)	(15)	6
Other comprehensive (loss) income before reclassifications	10	6	(13)
Amounts reclassified from AOCI	(6)	(6)	(8)
Net current period other comprehensive (loss) income	4	0	(21)
Accumulated other comprehensive income (loss), ending balance	(10)	(14)	(15)
Changes in Fair Value of Effective Cash Flow Hedges
Accumulated Other Comprehensive Income [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification		0
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated other comprehensive income (loss), beginning balance	2	(1)	13
Other comprehensive (loss) income before reclassifications	5	11	(13)
Amounts reclassified from AOCI	(6)	(8)	(1)
Net current period other comprehensive (loss) income	(1)	3	(14)
Accumulated other comprehensive income (loss), ending balance	$ 1	$ 2	$ (1)