Derivative Financial Instruments - Notional Amount, Estimated Fair Value and Maturity of Derivative Financial Instruments (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Derivatives designated as hedging instruments
Assets
Fair value	$ 13	$ 0
Liabilities
Fair value		0
Derivatives designated as hedging instruments | Assets
Assets
Notional amount		85
Fair value		0
Derivatives designated as hedging instruments | Interest rate swaps on commercial loans
Assets
Fair value	13
Derivatives designated as hedging instruments | Interest rate swaps on commercial loans | Assets
Assets
Notional amount	2,800
Fair value	13
Derivatives designated as hedging instruments | Interest rate swaps on custodial deposits
Liabilities
Fair value		0
Derivatives designated as hedging instruments | Interest rate swaps on custodial deposits | Liabilities
Liabilities
Notional amount		800
Fair value		0
Derivatives designated as hedging instruments | Interest rate swaps on AFS securities
Assets
Fair value		0
Liabilities
Fair value		0
Derivatives designated as hedging instruments | Interest rate swaps on AFS securities | Assets
Assets
Notional amount		85
Fair value		0
Derivatives designated as hedging instruments | Interest rate swaps on AFS securities | Liabilities
Liabilities
Notional amount		350
Fair value		0
Derivatives designated as hedging instruments | Interest rate swaps on HFI residential first mortgages
Liabilities
Fair value		0
Derivatives designated as hedging instruments | Interest rate swaps on HFI residential first mortgages | Liabilities
Liabilities
Notional amount		100
Fair value		0
Derivatives designated as hedging instruments | Interest rate swaps on subordinated debt
Assets
Fair value	0
Derivatives designated as hedging instruments | Fair Value Hedging | Assets
Assets
Notional amount	150
Fair value	0
Derivatives designated as hedging instruments | Fair Value Hedging | Liabilities
Liabilities
Notional amount		450
Fair value		0
Derivatives designated as hedging instruments | Fair Value Hedging | Interest rate swaps on subordinated debt | Assets
Assets
Notional amount	150
Fair value	0
Derivatives not designated as hedging instruments
Assets
Fair value	215	87
Liabilities
Fair value	72	20
Derivatives not designated as hedging instruments | Assets
Assets
Notional amount	16,148	14,364
Fair value	249	141
Derivatives not designated as hedging instruments | Liabilities
Liabilities
Notional amount	6,092	5,886
Fair value	81	20
Derivatives not designated as hedging instruments | Futures
Assets
Fair value	2
Derivatives not designated as hedging instruments | Futures | Assets
Assets
Notional amount	978	1,117
Fair value	2	0
Derivatives not designated as hedging instruments | Mortgage-backed securities forwards
Assets
Fair value	43	10
Liabilities
Fair value	31	14
Derivatives not designated as hedging instruments | Mortgage-backed securities forwards | Assets
Assets
Notional amount	3,366	4,008
Fair value	43	11
Derivatives not designated as hedging instruments | Mortgage-backed securities forwards | Liabilities
Liabilities
Notional amount	2,831	4,023
Fair value	31	14
Derivatives not designated as hedging instruments | Rate lock commitments | Assets
Assets
Notional amount	4,577	5,169
Fair value	34	54
Derivatives not designated as hedging instruments | Rate lock commitments | Liabilities
Liabilities
Notional amount	999	370
Fair value	9	1
Derivatives not designated as hedging instruments | Interest rate swaps and swaptions
Assets
Fair value	170
Derivatives not designated as hedging instruments | Interest rate swaps and swaptions | Assets
Assets
Notional amount	7,227	4,070
Fair value	170	76
Derivatives not designated as hedging instruments | Interest rate swaps and swaptions | Liabilities
Liabilities
Notional amount		1,493
Fair value		5
Derivatives not designated as hedging instruments | Interest rate swaps
Liabilities
Fair value	41	$ 6
Derivatives not designated as hedging instruments | Interest rate swaps | Liabilities
Liabilities
Notional amount	2,262
Fair value	$ 41