Borrowings - Interest on Debt (Details) - USD ($) $ in Millions	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020
Interest on Debt
Interest paid	$ 46	$ 47

Amount of the cost of borrowed funds accounted for as interest expense for debt.

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