Derivative Financial Instruments - Carrying Value of Hedged Items in Fair Value Hedge (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Derivatives, Fair Value [Line Items]
Carrying amount of hedged items	$ 13,299	$ 15,034
Active hedged asset adjustments	(1,565)	(1,633)
Discontinued hedged asset adjustments	155	246
Total hedged asset adjustments	$ (1,410)	$ (1,387)
Hedged Asset, Statement of Financial Position [Extensible Enumeration]	Securities available-for-sale (includes amortized cost of $29.1 billion and $30.3 billion at June 30, 2023 and December 31, 2022, respectively, an allowance for credit losses of nil at both June 30, 2023 and December 31, 2022, and $155 million and $55 million pledged to creditors at June 30, 2023 and December 31, 2022, respectively)	Securities available-for-sale (includes amortized cost of $29.1 billion and $30.3 billion at June 30, 2023 and December 31, 2022, respectively, an allowance for credit losses of nil at both June 30, 2023 and December 31, 2022, and $155 million and $55 million pledged to creditors at June 30, 2023 and December 31, 2022, respectively)
Deposits
Derivatives, Fair Value [Line Items]
Carrying amount of hedged liability items	$ 1,437	$ 1,446
Active hedged liability adjustments	(145)	(150)
Discontinued hedged liability adjustments	82	96
Total hedged liability adjustments	(63)	(54)
Long-term debt
Derivatives, Fair Value [Line Items]
Carrying amount of hedged liability items	7,452	6,506
Active hedged liability adjustments	(581)	(605)
Discontinued hedged liability adjustments	92	111
Total hedged liability adjustments	$ (489)	$ (494)