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%

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.

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)

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration