Basis of Presentation and Summary of Significant Accounting Policies (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
Jun. 30, 2019 |
Jun. 30, 2018 |
Jun. 30, 2019 |
Jun. 30, 2018 |
Jan. 01, 2019 |
Dec. 31, 2018 |
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| Accounting Policies [Line Items] | ||||||||||
| Gain on Business Interruption Insurance Recovery | $ 0 | $ 14 | $ 0 | $ 14 | ||||||
| Operating Lease, Right-of-Use Asset | [1],[2] | 184 | 184 | |||||||
| Interest costs capitalized | 1 | $ 7 | 8 | $ 14 | ||||||
| Current | 182 | 182 | $ 167 | |||||||
| Non-current | 80 | 80 | 34 | |||||||
| Total | 262 | 262 | 201 | |||||||
| Debt service | ||||||||||
| Accounting Policies [Line Items] | ||||||||||
| Current | 51 | 51 | 13 | |||||||
| Non-current | 8 | 8 | 8 | |||||||
| Total | 59 | 59 | 21 | |||||||
| Construction major maintenance | ||||||||||
| Accounting Policies [Line Items] | ||||||||||
| Current | 9 | 9 | 23 | |||||||
| Non-current | 39 | 39 | 24 | |||||||
| Total | 48 | 48 | 47 | |||||||
| Security project insurance | ||||||||||
| Accounting Policies [Line Items] | ||||||||||
| Current | 112 | 112 | 120 | |||||||
| Non-current | 31 | 31 | 0 | |||||||
| Total | 143 | 143 | 120 | |||||||
| Other | ||||||||||
| Accounting Policies [Line Items] | ||||||||||
| Current | 10 | 10 | 11 | |||||||
| Non-current | 2 | 2 | 2 | |||||||
| Total | $ 12 | $ 12 | $ 13 | |||||||
| Accounting Standards Update 2016-02 [Member] | ||||||||||
| Accounting Policies [Line Items] | ||||||||||
| Operating Lease, Right-of-Use Asset | $ 191 | |||||||||
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