v3.19.3.a.u2

Commitments and Contingencies (Schedules of Future Minimum Rental Payments) (Details) - USD ($) $ in Millions | Dec. 31, 2019 | Dec. 31, 2018
--- | --- | ---
Operating Leased Assets [Line Items] |  |  |
Operating Leases, Future Minimum Payments Due, Next Twelve Months | [1] |  | $ 50
Operating Leases, Future Minimum Payments, Due in Two Years | [1] |  | 19
Operating Leases, Future Minimum Payments, Due in Three Years | [1] |  | 20
Operating Leases, Future Minimum Payments, Due in Four Years | [1] |  | 18
Operating Leases, Future Minimum Payments, Due in Five Years | [1] |  | 17
Operating Leases, Future Minimum Payments, Due Thereafter | [1] |  | 192
Operating Leases, Future Minimum Payments Due | [1] |  | $ 316
Natural Gas [Member] |  |  |
Operating Leased Assets [Line Items] |  |  |
Operating Leases, Future Minimum Payments Due, Next Twelve Months |  | $ 402 |
Operating Leases, Future Minimum Payments, Due in Two Years |  | 178 |
Operating Leases, Future Minimum Payments, Due in Three Years |  | 121 |
Operating Leases, Future Minimum Payments, Due in Four Years |  | 98 |
Operating Leases, Future Minimum Payments, Due in Five Years |  | 41 |
Operating Leases, Future Minimum Payments, Due Thereafter |  | 103 |
Operating Leases, Future Minimum Payments Due |  | $ 943 |
[1] | During the years ended December 31, 2018 and 2017, expense for operating leases amounted to $53 million and $50 million, respectively.

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