Financial Instruments Cross-currency forward-exchange contracts (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Foreign Currency Fair Value Hedge Derivative [Line Items]
Unrealized gains on derivatives for net investment hedges, net	$ 25	$ 17
Derivatives Designated as Hedging Instruments: \| Forward-starting interest rate swap contracts
Foreign Currency Fair Value Hedge Derivative [Line Items]
Unrealized gains on derivatives for net investment hedges, net	39	(27)
Derivatives Designated as Hedging Instruments: \| Cross-currency interest rate swap contracts
Foreign Currency Fair Value Hedge Derivative [Line Items]
Unrealized gains on derivatives for net investment hedges, net	$ 25	$ 17

Amount, after tax, of reclassification from accumulated other comprehensive income (AOCI) of gain (loss) from increase (decrease) in fair value of net investment hedge.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4CCC
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL109998896-113959

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 10A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118930883&loc=SL7669646-108580

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration