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Debt - Schedule of Commercial Paper (Details) - Commercial paper - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Jun. 30, 2020 | Jun. 30, 2019 | Jun. 30, 2020 | Jun. 30, 2019 | Dec. 31, 2019
Debt Instrument [Line Items] |  |  |  |  |
Commercial paper outstanding | $ 336 |  | $ 336 |  | $ 112
Weighted average commercial paper outstanding | $ 808 | $ 639 | $ 632 | $ 482 |
Weighted average interest rate of commercial paper outstanding | 1.63% | 0.70% | 1.39% | 0.63% |

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