Property, Equipment and Right-of-Use Assets - Maturities of Operating Lease Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Operating Leases after Adoption of ASC Topic 842:
Remainder of 2019	$ 68
2020	81
2021	61
2022	55
2023	49
Thereafter	134
Total operating lease payments	448
Less: Interest	(42)
Present value of operating lease liabilities	$ 406
Operating Leases before Adoption of ASC Topic 842:
2019		$ 72
2020		75
2021		76
2022		68
2023		58
Thereafter		327
Total		$ 676

Amount of lessee's undiscounted obligation for lease payments for operating lease.

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