Fair Value Measurement - Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Jun. 30, 2024	Dec. 31, 2023	Jun. 30, 2023
Assets:
Fair Value		$ 79,250	$ 79,117
Loans held for sale		$ 394	$ 347
Derivative Asset, Statement of Financial Position [Extensible Enumeration]		Other assets	Other assets
Other assets:
Derivative assets, gross amount		$ 2,456	$ 2,675
Derivative Asset, netting adjustments		(1,034)	(1,005)
Derivative asset		1,422	1,670
Liabilities:
Derivative liabilities, gross amount		2,773	2,932
Derivative Liability, netting adjustments		(371)	(597)
Derivative liability		$ 2,402	$ 2,335
Derivative Liability, Statement of Financial Position [Extensible Enumeration]		Other liabilities	Other liabilities
Net valuation allowance		$ 3	$ 2
Level 1
Assets:
Loans held for sale		0	0
Level 2
Assets:
Loans held for sale		426	515
Level 3
Assets:
Loans held for sale		0	0
Recurring
Assets:
Fair Value		79,250	79,117
Loans held for sale		394	347
Other assets:
Derivative asset		1,422	1,670
Other		678	627
Total		81,744	81,761
Liabilities:
Derivative liability		2,402	2,335
Recurring | Level 1
Assets:
Fair Value		6,161	5,408
Loans held for sale		0	0
Other assets:
Derivative assets, gross amount		616	788
Other		644	589
Total		7,421	6,785
Liabilities:
Derivative liabilities, gross amount		511	449
Deferred compensation plan assets		644	578
Recurring | Level 2
Assets:
Fair Value		72,783	73,431
Loans held for sale		394	347
Other assets:
Derivative assets, gross amount		931	1,001
Other		0	3
Total		74,108	74,782
Liabilities:
Derivative liabilities, gross amount		1,422	1,655
Recurring | Level 3
Assets:
Fair Value		306	278
Loans held for sale		0	0
Other assets:
Derivative assets, gross amount		909	886	$ 1,200
Other		34	35
Total		1,249	1,199
Liabilities:
Derivative liabilities, gross amount		840	828	$ 1,100
Retained interests in securitizations		34	35
Recurring | Fair Value Inputs Level 1 And Level 2
Liabilities:
Equity securities			14
Debt and equity securities, unrealized gain (loss)	$ 5
U.S. Treasury securities
Assets:
Fair Value		6,029	5,282
U.S. Treasury securities | Recurring
Assets:
Fair Value		6,029	5,282
U.S. Treasury securities | Recurring | Level 1
Assets:
Fair Value		6,029	5,282
U.S. Treasury securities | Recurring | Level 2
Assets:
Fair Value		0	0
U.S. Treasury securities | Recurring | Level 3
Assets:
Fair Value		0	0
Total RMBS
Assets:
Fair Value		62,474	63,638
Total RMBS | Recurring
Assets:
Fair Value		62,474	63,638
Total RMBS | Recurring | Level 1
Assets:
Fair Value		0	0
Total RMBS | Recurring | Level 2
Assets:
Fair Value		62,170	63,492
Total RMBS | Recurring | Level 3
Assets:
Fair Value		304	146
CMBS | Recurring
Assets:
Fair Value		8,200	8,323
CMBS | Recurring | Level 1
Assets:
Fair Value		0	0
CMBS | Recurring | Level 2
Assets:
Fair Value		8,198	8,191
CMBS | Recurring | Level 3
Assets:
Fair Value		2	132
Other securities
Assets:
Fair Value		2,547	1,874
Other securities | Recurring
Assets:
Fair Value		2,547	1,874
Other securities | Recurring | Level 1
Assets:
Fair Value		132	126
Other securities | Recurring | Level 2
Assets:
Fair Value		2,415	1,748
Other securities | Recurring | Level 3
Assets:
Fair Value		$ 0	$ 0