Leases (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Lessee, Lease, Description [Line Items]
Operating lease expense	$ 40
Variable lease payments not included in the measurement of lease liabilities	21
Short-term lease payments not included in the measurement of lease liabilities	9
Cash paid for amounts included in the measurement of lease liabilities	42
Lease obligations obtained in exchange for right-of-use assets (non-cash)	241
Operating lease right of use assets	189	$ 0
Operating lease liabilities - current (in Other current liabilities)	35
Operating lease liabilities - noncurrent	164	0
Total operating lease liabilities	$ 199
Weighted-average remaining lease term—operating leases (years)	7 years 1 month 13 days
Weighted-average discount rate—operating leases	3.67%
2020	$ 42
2021	36
2022	32
2023	26
2024	22
After 2024	67
Total Lease Payments	225
Less: Imputed Interest	$ (26)
2019		38
2020		30
2021		24
2022		21
2023		15
After 2023		45
Total		173
Total rent expense		$ 45	$ 27
Minimum
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract	1 year
Maximum
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract	15 years