Leases (Details 3) $ in Millions	3 Months Ended
	Mar. 31, 2019 USD ($)
Operating Leases
2019	$ 24
2020	36
2021	34
2022	33
2023	30
2024	25
Thereafter	95
Total lease payments	277
Less imputed interest	(58)
Total net present value	219
Finance Leases
2019	16
2020	19
2021	17
2022	14
2023	8
2024	4
Thereafter	12
Total lease payments	90
Less imputed interest	(19)
Total net present value	71
Total
2019	40
2020	55
2021	51
2022	47
2023	38
2024	29
Thereafter	107
Total lease payments	367
Less imputed interest	(77)
Total net present value	290
Sublease receipts	$ 30
Term of sublease income	14 years
Operating lease not yet commenced	$ 15
Minimum
Lessee, Lease, Description [Line Items]
Renewal term of lease yet to be commenced	3 years
Maximum
Lessee, Lease, Description [Line Items]
Renewal term of lease yet to be commenced	10 years