Derivative Financial Instruments - Derivatives Subject to a Master Netting Arrangement (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Assets
Gross Amounts Not Offset in the Statement of Financial Condition, Cash Collateral	$ 79	$ 12
Liabilities
Gross Amounts Not Offset in the Statement of Financial Condition, Cash Collateral	113	66
Derivatives designated as hedging instruments
Assets
Gross Amount	13	0
Gross Amounts Netted in the Statements of Financial Condition	0	0
Net Amount Presented in the Statements of Financial Condition	13	0
Gross Amounts Not Offset in the Statement of Financial Condition, Financial Instruments	0	0
Gross Amounts Not Offset in the Statement of Financial Condition, Cash Collateral	43	1
Liabilities
Gross Amount		0
Gross Amounts Netted in the Statements of Financial Condition		0
Net Amount Presented in the Statements of Financial Condition		0
Gross Amounts Not Offset in the Statement of Financial Condition, Financial Instruments		0
Gross Amounts Not Offset in the Statement of Financial Condition, Cash Collateral		14
Derivatives designated as hedging instruments | Interest rate swaps on AFS securities
Assets
Gross Amount		0
Gross Amounts Netted in the Statements of Financial Condition		0
Net Amount Presented in the Statements of Financial Condition		0
Gross Amounts Not Offset in the Statement of Financial Condition, Financial Instruments		0
Gross Amounts Not Offset in the Statement of Financial Condition, Cash Collateral		1
Liabilities
Gross Amount		0
Gross Amounts Netted in the Statements of Financial Condition		0
Net Amount Presented in the Statements of Financial Condition		0
Gross Amounts Not Offset in the Statement of Financial Condition, Financial Instruments		0
Gross Amounts Not Offset in the Statement of Financial Condition, Cash Collateral		4
Derivatives designated as hedging instruments | Interest rate swaps on subordinated debt
Assets
Gross Amount	0
Gross Amounts Netted in the Statements of Financial Condition	0
Net Amount Presented in the Statements of Financial Condition	0
Gross Amounts Not Offset in the Statement of Financial Condition, Financial Instruments	0
Gross Amounts Not Offset in the Statement of Financial Condition, Cash Collateral	2
Derivatives designated as hedging instruments | Interest rate swaps on commercial loans
Assets
Gross Amount	13
Gross Amounts Netted in the Statements of Financial Condition	0
Net Amount Presented in the Statements of Financial Condition	13
Gross Amounts Not Offset in the Statement of Financial Condition, Financial Instruments	0
Gross Amounts Not Offset in the Statement of Financial Condition, Cash Collateral	41
Derivatives designated as hedging instruments | Interest rate swaps on HFI residential first mortgages
Liabilities
Gross Amount		0
Gross Amounts Netted in the Statements of Financial Condition		0
Net Amount Presented in the Statements of Financial Condition		0
Gross Amounts Not Offset in the Statement of Financial Condition, Financial Instruments		0
Gross Amounts Not Offset in the Statement of Financial Condition, Cash Collateral		1
Derivatives designated as hedging instruments | Interest rate swaps on custodial deposits
Liabilities
Gross Amount		0
Gross Amounts Netted in the Statements of Financial Condition		0
Net Amount Presented in the Statements of Financial Condition		0
Gross Amounts Not Offset in the Statement of Financial Condition, Financial Instruments		0
Gross Amounts Not Offset in the Statement of Financial Condition, Cash Collateral		9
Derivatives not designated as hedging instruments
Assets
Gross Amount	215	87
Gross Amounts Netted in the Statements of Financial Condition	0	0
Net Amount Presented in the Statements of Financial Condition	215	87
Gross Amounts Not Offset in the Statement of Financial Condition, Financial Instruments	0	0
Gross Amounts Not Offset in the Statement of Financial Condition, Cash Collateral	102	29
Liabilities
Gross Amount	72	20
Gross Amounts Netted in the Statements of Financial Condition	0	0
Net Amount Presented in the Statements of Financial Condition	72	20
Gross Amounts Not Offset in the Statement of Financial Condition, Financial Instruments	0	0
Gross Amounts Not Offset in the Statement of Financial Condition, Cash Collateral	46	33
Derivatives not designated as hedging instruments | Mortgage-backed securities forwards
Assets
Gross Amount	43	10
Gross Amounts Netted in the Statements of Financial Condition	0	0
Net Amount Presented in the Statements of Financial Condition	43	10
Gross Amounts Not Offset in the Statement of Financial Condition, Financial Instruments	0	0
Gross Amounts Not Offset in the Statement of Financial Condition, Cash Collateral	40	12
Liabilities
Gross Amount	31	14
Gross Amounts Netted in the Statements of Financial Condition	0	0
Net Amount Presented in the Statements of Financial Condition	31	14
Gross Amounts Not Offset in the Statement of Financial Condition, Financial Instruments	0	0
Gross Amounts Not Offset in the Statement of Financial Condition, Cash Collateral	12	9
Derivatives not designated as hedging instruments | Interest rate swaps and swaptions
Assets
Gross Amount	170
Gross Amounts Netted in the Statements of Financial Condition	0
Net Amount Presented in the Statements of Financial Condition	170
Gross Amounts Not Offset in the Statement of Financial Condition, Financial Instruments	0
Gross Amounts Not Offset in the Statement of Financial Condition, Cash Collateral	60
Derivatives not designated as hedging instruments | Futures
Assets
Gross Amount	2
Gross Amounts Netted in the Statements of Financial Condition	0
Net Amount Presented in the Statements of Financial Condition	2
Gross Amounts Not Offset in the Statement of Financial Condition, Financial Instruments	0
Gross Amounts Not Offset in the Statement of Financial Condition, Cash Collateral	2
Derivatives not designated as hedging instruments | Interest rate swaps
Liabilities
Gross Amount	41	6
Gross Amounts Netted in the Statements of Financial Condition	0	0
Net Amount Presented in the Statements of Financial Condition	41	6
Gross Amounts Not Offset in the Statement of Financial Condition, Financial Instruments	0	0
Gross Amounts Not Offset in the Statement of Financial Condition, Cash Collateral	$ 34	24
Derivatives not designated as hedging instruments | Interest rate swaptions
Assets
Gross Amount		77
Gross Amounts Netted in the Statements of Financial Condition		0
Net Amount Presented in the Statements of Financial Condition		77
Gross Amounts Not Offset in the Statement of Financial Condition, Financial Instruments		0
Gross Amounts Not Offset in the Statement of Financial Condition, Cash Collateral		$ 17