Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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-Publisher FASB
-Name Accounting Standards Codification
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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Derivatives and Risk Management (Narrative) (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Interest rate swaps
Derivative [Line Items]
Derivative asset	$ 1
Not Designated as Hedging Instrument
Derivative [Line Items]
Fair value of net derivative liability position decrease	7	$ 1
Not Designated as Hedging Instrument \| Commodities
Derivative [Line Items]
Derivative liability	3,491
Not Designated as Hedging Instrument \| Interest rate swaps
Derivative [Line Items]
Derivative asset	$ 1