Derivative Instruments (Details 5) (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Jun. 30, 2019 |
Jun. 30, 2018 |
Jun. 30, 2019 |
Jun. 30, 2018 |
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| Derivative Instruments, Gain (Loss) [Line Items] | |||||||||||||
| Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, before Tax | $ (32) | $ 15 | $ (57) | $ 70 | |||||||||
| Reclassification adjustment for loss on cash flow hedges realized in net income (loss) | [1],[2] | 3 | 0 | 5 | (7) | ||||||||
| Depreciation expense [Member] | |||||||||||||
| Derivative Instruments, Gain (Loss) [Line Items] | |||||||||||||
| Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, before Tax | [3],[4] | 0 | 1 | ||||||||||
| Reclassification adjustment for loss on cash flow hedges realized in net income (loss) | [1],[2],[3],[4] | 0 | (1) | ||||||||||
| Interest Rate Hedging Instruments | |||||||||||||
| Derivative Instruments, Gain (Loss) [Line Items] | |||||||||||||
| Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, before Tax | [3],[4] | (32) | 15 | (57) | 69 | ||||||||
| Reclassification adjustment for loss on cash flow hedges realized in net income (loss) | [1],[2],[3],[4] | $ 3 | $ 0 | $ 5 | $ (6) | ||||||||
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