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Debt - Schedule of Commercial Paper (Details) - Commercial paper - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2021 | Jun. 30, 2020 | Jun. 30, 2021 | Jun. 30, 2020
Debt Instrument [Line Items] |  |  |  |
Weighted average commercial paper outstanding | $ 65 | $ 808 | $ 41 | $ 632
Weighted average interest rate of commercial paper outstanding | 0.17% | 1.63% | 0.18% | 1.39%

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- Definition For the form of debt having an initial term of less than one year or less than the normal operating cycle, if longer, average borrowings during the period. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher SEC -Name Regulation S-K (SK) -Number 229 -Section 1402 -Paragraph (a) Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher SEC -Name Regulation S-K (SK) -Number 229 -Section 1402 -Paragraph (b) -Subparagraph (1) + Details
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