Employee Benefit Plans - Schedule of Benefit Obligation and Plan Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Pension Benefits
Change in benefit obligation:
Benefit obligation at beginning of year	$ 2,418	$ 820
Service cost	21	37	$ 18
Interest cost	71	51	34
Plan amendment	20	0
Actuarial loss (gain)	(93)	41
Benefits paid	(67)	(65)
Curtailments	(7)	(45)
Settlements	(59)	(10)
Business acquisition	0	1,546
Other	16	(2)
Foreign currency translation adjustments	59	(45)
Benefit obligation at end of year	2,261	2,418	820
Change in plan assets:
Fair value of plan assets at beginning of year	2,059	567
Actual return on plan assets	(60)	152
Employer contributions	51	50
Benefits paid	(67)	(65)
Settlements	(59)	(10)
Business acquisition	0	1,342
Other	(9)	(2)
Foreign currency translation adjustments	(49)	25
Fair value of plan assets at end of year	1,866	2,059	567
Funded status - underfunded at end of year	(395)	(359)
Accumulated benefit obligation	2,225	2,373
Other Postretirement Benefits
Change in benefit obligation:
Benefit obligation at beginning of year	187	117
Service cost	2	2	2
Interest cost	5	6	5
Plan amendment	1	(23)
Actuarial loss (gain)	(23)	0
Benefits paid	(21)	(13)
Curtailments	(5)	5
Settlements	0	0
Business acquisition	0	93
Other	(39)	0
Foreign currency translation adjustments	0	0
Benefit obligation at end of year	107	187	117
Change in plan assets:
Fair value of plan assets at beginning of year	0	0
Actual return on plan assets	0	0
Employer contributions	21	13
Benefits paid	(21)	(13)
Settlements	0	0
Business acquisition	0	0
Other	0	0
Foreign currency translation adjustments	0	0
Fair value of plan assets at end of year	0	0	$ 0
Funded status - underfunded at end of year	(107)	(187)
Accumulated benefit obligation	$ 107	$ 187