Accumulated other comprehensive income (loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accumulated Other Comprehensive Income (Loss)
Balance at the beginning of period	$ 761
Reclassification to gain on disposal of discontinued operations	(68)
Balance at the end of period	935	$ 761
Accumulated other comprehensive income (loss)
Accumulated Other Comprehensive Income (Loss)
Balance at the beginning of period	41	64	$ 95
Other comprehensive (loss) income	(93)	(24)	(33)
Tax benefit (expense)		1	2
Reclassification to gain on disposal of discontinued operations	(68)
Balance at the end of period	(120)	41	64
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss)
Balance at the beginning of period	126	111	130
Other comprehensive (loss) income	(47)	14	(19)
Tax benefit (expense)		1
Reclassification to gain on disposal of discontinued operations	(78)
Balance at the end of period	1	126	111
Net (Loss) Income Hedge Investments in Foreign Operations
Accumulated Other Comprehensive Income (Loss)
Balance at the beginning of period		51
Balance at the end of period			51
Unrecognized (Loss) Gain on Derivative Instruments
Accumulated Other Comprehensive Income (Loss)
Balance at the beginning of period	(12)		7
Other comprehensive (loss) income	(3)	(12)	(10)
Tax benefit (expense)			3
Reclassification to gain on disposal of discontinued operations	(5)
Balance at the end of period	(20)	(12)
Pension Adjustments
Accumulated Other Comprehensive Income (Loss)
Balance at the beginning of period	(73)	(47)	(42)
Other comprehensive (loss) income	(43)	(26)	(4)
Tax benefit (expense)			(1)
Reclassification to gain on disposal of discontinued operations	15
Balance at the end of period	$ (101)	$ (73)	$ (47)