Borrowed Funds - Details of Repurchase Agreements (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Contractual Maturity Over 90 days, amount	$ 800	$ 800
Maturity Greater than 90 Days [Member]
Debt Instrument [Line Items]
Contractual Maturity Over 90 days, amount	$ 800
Contractual Maturity Over 90 days, Weighted Average Interest Rate	2.24%
Mortgage-Related Securities \| Maturity Greater than 90 Days [Member]
Debt Instrument [Line Items]
Contractual Maturity Over 90 days, Amortized Cost	$ 345
Contractual Maturity Over 90 days, Fair Value	343
U.S. Treasury and GSE Obligations \| Maturity Greater than 90 Days [Member]
Debt Instrument [Line Items]
Contractual Maturity Over 90 days, Amortized Cost	549
Contractual Maturity Over 90 days, Fair Value	$ 570

Securities Held as Collateral, at Amortized Cost

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Interest rate on the amount to be repaid to the counterparty to the repurchase agreement when the carrying amount (or market value, if higher than the carrying amount) of securities or other assets sold under the repurchase agreement exceeds 10 percent of total assets.

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The carrying amount (fair value) as of the balance sheet date of securities held that had been pledged by counterparties under financing and lending arrangements, pursuant to which the entity has the right by agreement or custom to sell or re-pledge such securities.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Amount, after the effects of master netting arrangements, of funds outstanding borrowed in the form of a security repurchase agreement between the entity and another party for the sale and repurchase of identical or substantially the same securities at a date certain for a specified price. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
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