Employee Benefit Plans - Funded Status (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018
Amounts recognized in balance sheet:
Noncurrent asset				$ 79	$ 46
Defined Benefit Plans
Change in benefit obligation
Benefit obligation at beginning of year	$ 1,021	$ 1,136
Service cost	3	5	$ 5
Interest cost	24	25	25
Actuarial loss (gain)	108	(60)
Gross benefits paid	(52)	(58)
Plan amendments	0	6
Exchange rates	17	(56)
Curtailments	(21)	23
Benefit obligation at end of year	1,100	1,021	1,136
Accumulated benefit obligation at end of year				1,076	983
Change in plan assets
Fair value of plan assets at beginning of year	813	906
Actual return on plan assets	108	(34)
Employer contribution	40	47
Gross benefits paid	(52)	(58)
Exchange rates	24	(48)
Other	1	0
Fair value of plan assets at end of year	934	813	906
Funded status
Fair value of plan assets	813	813	906	934	813
Benefit obligation	(1,100)	(1,136)	(1,136)	(1,100)	(1,021)
Accrued benefit cost				(166)	(208)
Amounts recognized in balance sheet:
Noncurrent asset				79	46
Current liability				(1)	(1)
Noncurrent liability				(244)	(253)
Total				(166)	(208)
Amounts recognized in accumulated other comprehensive loss:
Net actuarial loss (gain)				321	302
Prior service cost (credit)				5	11
Total				326	313
Amounts in accumulated other comprehensive (loss) income that are expected to be recognized as components of net periodic benefit cost during the next fiscal year
Actuarial loss				13
Prior service cost				1
Total				14
Components of net periodic benefit cost
Service cost	3	5	5
Interest cost	24	25	25
Expected return on plan assets	(42)	(47)	(43)
Amortization of actuarial loss	14	15	16
Amortization of prior service cost	1	3	1
Curtailments	(9)	23	(4)
Net periodic benefit cost	(9)	24	0
Other Postretirement Benefit Plans
Change in benefit obligation
Benefit obligation at beginning of year	3	3
Service cost	0	0
Interest cost	0	0
Actuarial loss (gain)	1	0
Gross benefits paid	(1)	0
Plan amendments	0	0
Exchange rates	0	0
Curtailments	0	0
Benefit obligation at end of year	3	3	3
Change in plan assets
Fair value of plan assets at beginning of year	0	0
Actual return on plan assets	0	0
Employer contribution	0	0
Gross benefits paid	0	0
Exchange rates	0	0
Other	0	0
Fair value of plan assets at end of year	0	0	0
Funded status
Fair value of plan assets	0	0	0	0	0
Benefit obligation	(3)	(3)	(3)	(3)	(3)
Accrued benefit cost				(3)	(3)
Amounts recognized in balance sheet:
Noncurrent asset				0	0
Current liability				0	0
Noncurrent liability				(3)	(3)
Total				(3)	(3)
Amounts recognized in accumulated other comprehensive loss:
Net actuarial loss (gain)				(3)	(4)
Prior service cost (credit)				0	(1)
Total				(3)	$ (5)
Amounts in accumulated other comprehensive (loss) income that are expected to be recognized as components of net periodic benefit cost during the next fiscal year
Actuarial loss				0
Prior service cost				0
Total				$ 0
Components of net periodic benefit cost
Service cost	0	0
Interest cost	0	0
Amortization of actuarial loss	0	0	1
Amortization of prior service cost	0	0	(3)
Net periodic benefit cost	$ (1)	$ 0	$ (2)