Leases (Details) - USD ($)
$ in Millions |
12 Months Ended |
|
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
Jan. 01, 2019 |
| New Accounting Pronouncements or Change in Accounting Principle [Line Items] |
|
|
|
|
| Operating lease right-of-use assets |
$ 103
|
|
|
|
| Carrying value of finance lease assets |
147
|
$ 147
|
|
|
| Future minimum sublease rentals, 2021 |
|
15
|
|
|
| Future minimum sublease rentals, 2022 |
|
12
|
|
|
| Future minimum sublease rentals, 2023 |
|
11
|
|
|
| Future minimum sublease rentals, 2024 |
|
6
|
|
|
| Operating and financing leases, rent expense, net |
16
|
|
|
|
| Lease and rental expense |
|
$ 35
|
$ 29
|
|
| Facilities |
|
|
|
|
| New Accounting Pronouncements or Change in Accounting Principle [Line Items] |
|
|
|
|
| Future minimum sublease rentals, 2021 |
4
|
|
|
|
| Future minimum sublease rentals, 2022 |
4
|
|
|
|
| Future minimum sublease rentals, 2023 |
4
|
|
|
|
| Future minimum sublease rentals, 2024 |
$ 4
|
|
|
|
| Real Property |
|
|
|
|
| New Accounting Pronouncements or Change in Accounting Principle [Line Items] |
|
|
|
|
| Operating lease, term of contract |
40 years
|
|
|
|
| Vehicles |
|
|
|
|
| New Accounting Pronouncements or Change in Accounting Principle [Line Items] |
|
|
|
|
| Operating lease, term of contract |
7 years
|
|
|
|
| Equipment |
|
|
|
|
| New Accounting Pronouncements or Change in Accounting Principle [Line Items] |
|
|
|
|
| Operating lease, term of contract |
5 years
|
|
|
|
| Operating and Maintenance Agreement |
|
|
|
|
| New Accounting Pronouncements or Change in Accounting Principle [Line Items] |
|
|
|
|
| Future minimum sublease rentals, 2020 |
$ 4
|
|
|
|
| Future minimum sublease rentals, thereafter |
$ 54
|
|
|
|
| Minimum |
|
|
|
|
| New Accounting Pronouncements or Change in Accounting Principle [Line Items] |
|
|
|
|
| Operating lease, renewal term |
1 year
|
|
|
|
| Maximum |
|
|
|
|
| New Accounting Pronouncements or Change in Accounting Principle [Line Items] |
|
|
|
|
| Operating lease, renewal term |
60 years
|
|
|
|
| Utility Plant | Minimum |
|
|
|
|
| New Accounting Pronouncements or Change in Accounting Principle [Line Items] |
|
|
|
|
| Lessee, finance lease, term of contract |
30 years
|
|
|
|
| Utility Plant | Maximum |
|
|
|
|
| New Accounting Pronouncements or Change in Accounting Principle [Line Items] |
|
|
|
|
| Lessee, finance lease, term of contract |
40 years
|
|
|
|
| Accounting Standards Update 2016-02 |
|
|
|
|
| New Accounting Pronouncements or Change in Accounting Principle [Line Items] |
|
|
|
|
| Operating lease right-of-use assets |
|
|
|
$ 117
|
| Operating lease liabilities |
|
|
|
$ 115
|