Fair Value Measurement - Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2023	Dec. 31, 2022	Sep. 30, 2022
Assets:
Securities available for sale (amortized cost of $87.7 billion and $87.0 billion and allowance for credit losses of $4 million and $3 million as of September 30, 2023 and December 31, 2022, respectively)	$ 74,837.0	$ 76,919.0
Loans Held-for-sale, Fair Value Disclosure	314.0	191.0
Derivative assets, gross amount	3,381.0	3,098.0
Derivative asset, netting adjustments	(1,471.0)	(1,134.0)
Derivative asset	$ 1,910.0	1,964.0
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Other liabilities
Liabilities:
Derivative liabilities, gross amount	$ 3,699.0	4,550.0
Derivative liability, netting adjustments	(632.0)	(1,235.0)
Derivative liability	3,067.0	3,315.0
Net valuation allowance	1.0	4.0
Level 1
Assets:
Loans Held-for-sale, Fair Value Disclosure	0.0	0.0
Level 2
Assets:
Loans Held-for-sale, Fair Value Disclosure	440.0	11.0
Level 3
Assets:
Loans Held-for-sale, Fair Value Disclosure	0.0	0.0
Recurring
Assets:
Securities available for sale (amortized cost of $87.7 billion and $87.0 billion and allowance for credit losses of $4 million and $3 million as of September 30, 2023 and December 31, 2022, respectively)	74,837.0	76,919.0
Loans Held-for-sale, Fair Value Disclosure	314.0	191.0
Derivative asset	1,910.0	1,964.0
Other assets	567.0	503.0
Total assets	77,628.0	79,577.0
Liabilities:
Derivative liability	3,067.0	3,315.0
Recurring | Level 1
Assets:
Securities available for sale (amortized cost of $87.7 billion and $87.0 billion and allowance for credit losses of $4 million and $3 million as of September 30, 2023 and December 31, 2022, respectively)	5,397.0	5,227.0
Loans Held-for-sale, Fair Value Disclosure	0.0	0.0
Derivative assets, gross amount	725.0	474.0
Other assets	529.0	464.0
Total assets	6,651.0	6,165.0
Other assets:
Deferred compensation plan assets	524.0	453.0
Liabilities:
Derivative liabilities, gross amount	822.0	823.0
Recurring | Level 2
Assets:
Securities available for sale (amortized cost of $87.7 billion and $87.0 billion and allowance for credit losses of $4 million and $3 million as of September 30, 2023 and December 31, 2022, respectively)	69,165.0	71,314.0
Loans Held-for-sale, Fair Value Disclosure	314.0	191.0
Derivative assets, gross amount	1,333.0	2,545.0
Other assets	3.0	3.0
Total assets	70,815.0	74,053.0
Liabilities:
Derivative liabilities, gross amount	1,622.0	3,653.0
Recurring | Level 3
Assets:
Securities available for sale (amortized cost of $87.7 billion and $87.0 billion and allowance for credit losses of $4 million and $3 million as of September 30, 2023 and December 31, 2022, respectively)	275.0	378.0
Loans Held-for-sale, Fair Value Disclosure	0.0	0.0
Derivative assets, gross amount	1,323.0	79.0	$ 110.0
Other assets	35.0	36.0
Total assets	1,633.0	493.0
Other assets:
Retained interests in securitizations	35.0	36.0
Liabilities:
Derivative liabilities, gross amount	1,255.0	74.0	$ 115.0
Recurring | Fair Value Inputs Level 1 And Level 2 [Member]
Other assets:
Equity securities	8.0	14.0
Liabilities:
Debt and Equity Securities, Unrealized Gain (Loss)	(1.0)	(23.0)
U.S. Treasury securities
Assets:
Securities available for sale (amortized cost of $87.7 billion and $87.0 billion and allowance for credit losses of $4 million and $3 million as of September 30, 2023 and December 31, 2022, respectively)	5,205.0	5,041.0
U.S. Treasury securities | Recurring
Assets:
Securities available for sale (amortized cost of $87.7 billion and $87.0 billion and allowance for credit losses of $4 million and $3 million as of September 30, 2023 and December 31, 2022, respectively)	5,205.0	5,041.0
U.S. Treasury securities | Recurring | Level 1
Assets:
Securities available for sale (amortized cost of $87.7 billion and $87.0 billion and allowance for credit losses of $4 million and $3 million as of September 30, 2023 and December 31, 2022, respectively)	5,205.0	5,041.0
U.S. Treasury securities | Recurring | Level 2
Assets:
Securities available for sale (amortized cost of $87.7 billion and $87.0 billion and allowance for credit losses of $4 million and $3 million as of September 30, 2023 and December 31, 2022, respectively)	0.0	0.0
U.S. Treasury securities | Recurring | Level 3
Assets:
Securities available for sale (amortized cost of $87.7 billion and $87.0 billion and allowance for credit losses of $4 million and $3 million as of September 30, 2023 and December 31, 2022, respectively)	0.0	0.0
RMBS
Assets:
Securities available for sale (amortized cost of $87.7 billion and $87.0 billion and allowance for credit losses of $4 million and $3 million as of September 30, 2023 and December 31, 2022, respectively)	59,882.0	62,589.0
RMBS | Recurring
Assets:
Securities available for sale (amortized cost of $87.7 billion and $87.0 billion and allowance for credit losses of $4 million and $3 million as of September 30, 2023 and December 31, 2022, respectively)	59,882.0	62,589.0
RMBS | Recurring | Level 1
Assets:
Securities available for sale (amortized cost of $87.7 billion and $87.0 billion and allowance for credit losses of $4 million and $3 million as of September 30, 2023 and December 31, 2022, respectively)	0.0	0.0
RMBS | Recurring | Level 2
Assets:
Securities available for sale (amortized cost of $87.7 billion and $87.0 billion and allowance for credit losses of $4 million and $3 million as of September 30, 2023 and December 31, 2022, respectively)	59,733.0	62,353.0
RMBS | Recurring | Level 3
Assets:
Securities available for sale (amortized cost of $87.7 billion and $87.0 billion and allowance for credit losses of $4 million and $3 million as of September 30, 2023 and December 31, 2022, respectively)	149.0	236.0
CMBS | Recurring
Assets:
Securities available for sale (amortized cost of $87.7 billion and $87.0 billion and allowance for credit losses of $4 million and $3 million as of September 30, 2023 and December 31, 2022, respectively)	7,839.0	7,870.0
CMBS | Recurring | Level 1
Assets:
Securities available for sale (amortized cost of $87.7 billion and $87.0 billion and allowance for credit losses of $4 million and $3 million as of September 30, 2023 and December 31, 2022, respectively)	0.0	0.0
CMBS | Recurring | Level 2
Assets:
Securities available for sale (amortized cost of $87.7 billion and $87.0 billion and allowance for credit losses of $4 million and $3 million as of September 30, 2023 and December 31, 2022, respectively)	7,713.0	7,728.0
CMBS | Recurring | Level 3
Assets:
Securities available for sale (amortized cost of $87.7 billion and $87.0 billion and allowance for credit losses of $4 million and $3 million as of September 30, 2023 and December 31, 2022, respectively)	126.0	142.0
Other securities
Assets:
Securities available for sale (amortized cost of $87.7 billion and $87.0 billion and allowance for credit losses of $4 million and $3 million as of September 30, 2023 and December 31, 2022, respectively)	1,911.0	1,419.0
Other securities | Recurring
Assets:
Securities available for sale (amortized cost of $87.7 billion and $87.0 billion and allowance for credit losses of $4 million and $3 million as of September 30, 2023 and December 31, 2022, respectively)	1,911.0	1,419.0
Other securities | Recurring | Level 1
Assets:
Securities available for sale (amortized cost of $87.7 billion and $87.0 billion and allowance for credit losses of $4 million and $3 million as of September 30, 2023 and December 31, 2022, respectively)	192.0	186.0
Other securities | Recurring | Level 2
Assets:
Securities available for sale (amortized cost of $87.7 billion and $87.0 billion and allowance for credit losses of $4 million and $3 million as of September 30, 2023 and December 31, 2022, respectively)	1,719.0	1,233.0
Other securities | Recurring | Level 3
Assets:
Securities available for sale (amortized cost of $87.7 billion and $87.0 billion and allowance for credit losses of $4 million and $3 million as of September 30, 2023 and December 31, 2022, respectively)	$ 0.0	$ 0.0