FAIR VALUE MEASUREMENTS - Schedule of Fair Value Measurements (Details) - USD ($) $ in Millions		Sep. 30, 2023	Dec. 31, 2022
Assets
Fair Value	[1]	$ 25,069	$ 24,007
Loans held for sale, at fair value		749	774
Mortgage servicing rights		1,620	1,530
Derivative assets		1,698	1,839
Equity securities, at fair value		106	110
Total assets		29,242	28,260
Liabilities
Total derivative liabilities		2,948	3,111
Total liabilities		2,948	3,111
Equity securities excluded from investments		163	153
Interest rate contracts
Assets
Derivative assets		439	347
Liabilities
Total derivative liabilities		1,842	1,632
Foreign exchange contracts
Assets
Derivative assets		530	527
Liabilities
Total derivative liabilities		432	519
Commodities contracts
Assets
Derivative assets		707	953
Liabilities
Total derivative liabilities		666	942
TBA contracts
Assets
Derivative assets		17	7
Liabilities
Total derivative liabilities		5	14
Other contracts
Assets
Derivative assets		5	5
Liabilities
Total derivative liabilities		3	4
Level 1
Assets
Fair Value		3,774	3,486
Loans held for sale, at fair value		0	0
Derivative assets		0	0
Equity securities, at fair value		106	110
Total assets		3,880	3,596
Liabilities
Total derivative liabilities		0	0
Total liabilities		0	0
Level 1 | Interest rate contracts
Assets
Derivative assets		0	0
Liabilities
Total derivative liabilities		0	0
Level 1 | Foreign exchange contracts
Assets
Derivative assets		0	0
Liabilities
Total derivative liabilities		0	0
Level 1 | Commodities contracts
Assets
Derivative assets		0	0
Liabilities
Total derivative liabilities		0	0
Level 1 | TBA contracts
Assets
Derivative assets		0	0
Liabilities
Total derivative liabilities		0	0
Level 1 | Other contracts
Assets
Derivative assets		0	0
Liabilities
Total derivative liabilities		0	0
Level 2
Assets
Fair Value		21,295	20,521
Loans held for sale, at fair value		749	774
Derivative assets		1,693	1,834
Equity securities, at fair value		0	0
Total assets		23,737	23,129
Liabilities
Total derivative liabilities		2,946	3,107
Total liabilities		2,946	3,107
Level 2 | Interest rate contracts
Assets
Derivative assets		439	347
Liabilities
Total derivative liabilities		1,842	1,632
Level 2 | Foreign exchange contracts
Assets
Derivative assets		530	527
Liabilities
Total derivative liabilities		432	519
Level 2 | Commodities contracts
Assets
Derivative assets		707	953
Liabilities
Total derivative liabilities		666	942
Level 2 | TBA contracts
Assets
Derivative assets		17	7
Liabilities
Total derivative liabilities		5	14
Level 2 | Other contracts
Assets
Derivative assets		0	0
Liabilities
Total derivative liabilities		1	0
Level 3
Assets
Fair Value		0	0
Loans held for sale, at fair value		0	0
Derivative assets		5	5
Equity securities, at fair value		0	0
Total assets		1,625	1,535
Liabilities
Total derivative liabilities		2	4
Total liabilities		2	4
Level 3 | Interest rate contracts
Assets
Derivative assets		0	0
Liabilities
Total derivative liabilities		0	0
Level 3 | Foreign exchange contracts
Assets
Derivative assets		0	0
Liabilities
Total derivative liabilities		0	0
Level 3 | Commodities contracts
Assets
Derivative assets		0	0
Liabilities
Total derivative liabilities		0	0
Level 3 | TBA contracts
Assets
Derivative assets		0	0
Liabilities
Total derivative liabilities		0	0
Level 3 | Other contracts
Assets
Derivative assets		5	5
Liabilities
Total derivative liabilities		2	4
Fair Value Measured at Net Asset Value Per Share
Liabilities
Equity securities excluded from investments		57	43
Unfunded capital commitments		24	42
Mortgage-backed securities
Assets
Fair Value		20,504	19,313
Mortgage-backed securities | Level 1
Assets
Fair Value		0	0
Mortgage-backed securities | Level 2
Assets
Fair Value		20,504	19,313
Mortgage-backed securities | Level 3
Assets
Fair Value		0	0
Collateralized loan obligations
Assets
Fair Value		789	1,206
Collateralized loan obligations | Level 1
Assets
Fair Value		0	0
Collateralized loan obligations | Level 2
Assets
Fair Value		789	1,206
Collateralized loan obligations | Level 3
Assets
Fair Value		0	0
State and political subdivisions
Assets
Fair Value		2	2
State and political subdivisions | Level 1
Assets
Fair Value		0	0
State and political subdivisions | Level 2
Assets
Fair Value		2	2
State and political subdivisions | Level 3
Assets
Fair Value		0	0
U.S. Treasury and other
Assets
Fair Value		3,774	3,486
U.S. Treasury and other | Level 1
Assets
Fair Value		3,774	3,486
U.S. Treasury and other | Level 2
Assets
Fair Value		0	0
U.S. Treasury and other | Level 3
Assets
Fair Value		0	0
Residential loans held for sale
Assets
Loans held for sale, at fair value		739	666
Residential loans held for sale | Level 1
Assets
Loans held for sale, at fair value		0	0
Residential loans held for sale | Level 2
Assets
Loans held for sale, at fair value		739	666
Residential loans held for sale | Level 3
Assets
Loans held for sale, at fair value		0	0
Commercial loans held for sale
Assets
Loans held for sale, at fair value		10	108
Commercial loans held for sale | Level 1
Assets
Loans held for sale, at fair value		0	0
Commercial loans held for sale | Level 2
Assets
Loans held for sale, at fair value		10	108
Commercial loans held for sale | Level 3
Assets
Loans held for sale, at fair value		0	0
Mortgage servicing rights
Assets
Mortgage servicing rights		1,620	1,530
Mortgage servicing rights | Level 1
Assets
Mortgage servicing rights		0	0
Mortgage servicing rights | Level 2
Assets
Mortgage servicing rights		0	0
Mortgage servicing rights | Level 3
Assets
Mortgage servicing rights		$ 1,620	$ 1,530

[1] Includes only collateral pledged by the Company where counterparties have the right to sell or pledge the collateral.