Derivative Financial Instruments - Offsetting Derivative Financial Instruments (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Derivative assets
Gross Amount Recognized in the Condensed Consolidated Balance Sheets	$ 2,478	$ 2,862
Gross Amounts Not Offset in the Condensed Consolidated Balance Sheets, Derivatives	(540)	(621)
Gross Amounts Not Offset in the Condensed Consolidated Balance Sheets, Collateral	(657)	(755)
Net Amount	1,281	1,486
Derivative liabilities
Gross Amount Recognized in the Condensed Consolidated Balance Sheets	1,226	1,072
Gross Amounts Not Offset in the Condensed Consolidated Balance Sheets, Derivatives	(540)	(621)
Gross Amounts Not Offset in the Condensed Consolidated Balance Sheets, Collateral	(383)	(221)
Net Amount	$ 303	$ 230

Fair value, after the effects of master netting arrangements, of a financial asset or other 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 assets not subject to a master netting arrangement and not elected to be offset.

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