Postretirement Benefit Plans - Amounts Recognized on our Balance Sheet (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Overfunded retirement plans	$ 92	$ 208
Accrued expenses and other liabilities & other long-term liabilities	(11)	(18)
Underfunded retirement plans	(118)	(89)
Funded status at end of year	(37)	101
United States | Defined benefit plan
Defined Benefit Plan Disclosure [Line Items]
Overfunded retirement plans	40	58
Accrued expenses and other liabilities & other long-term liabilities	(8)	(13)
Underfunded retirement plans	(37)	(48)
Funded status at end of year	(5)	(3)
United States | Retiree health care plan
Defined Benefit Plan Disclosure [Line Items]
Overfunded retirement plans	0	0
Accrued expenses and other liabilities & other long-term liabilities	0	0
Underfunded retirement plans	(31)	(20)
Funded status at end of year	(31)	(20)
Non-U.S. | Defined benefit plan
Defined Benefit Plan Disclosure [Line Items]
Overfunded retirement plans	52	150
Accrued expenses and other liabilities & other long-term liabilities	(3)	(5)
Underfunded retirement plans	(50)	(21)
Funded status at end of year	$ (1)	$ 124