Recent Accounting Pronouncements Recent Accounting Pronouncements - Future Lease Payments for Operating Leases (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Maturity Of Lease Liabilities:
2019 (remaining)	$ 100
2020	105
2021	75
2022	52
2023	35
Thereafter	84
Total undiscounted operating lease payments	451
Less imputed interest	57
Present value of operating lease liabilities	$ 394
Operating Leases, Before Adoption of 842
2019		$ 153
2020		113
2021		78
2022		53
2023		33
Thereafter		76
Total minimum operating lease payments		$ 506

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

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