INVESTMENTS - Overview (Details) - USD ($) $ in Millions		1 Months Ended	3 Months Ended		6 Months Ended
		Jun. 30, 2022	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020
Investment Holdings
Total investments		$ 513,878	$ 513,878		$ 513,878			$ 512,822
Interest and dividends on investments
Taxable interest			2,274	$ 1,723	4,287	$ 3,375
Interest exempt from U.S. federal income tax			38	57	43	123
Dividend income			58	38	90	72
Total interest and dividend income on investments			2,370	1,818	4,420	3,570
Gross realized investments losses, excluding losses from other-than-temporary impairment
Gross realized investment gains			27	155	180	615
Gross realized investment losses			(85)	(18)	(158)	(77)
Net realized gains (losses) on sales of investments			(58)	137	22	538
Debt securities AFS
Allowance for credit losses		6	6	$ 5	6	5	$ 8	8	$ 5	$ 5
Fair value		238,499	238,499		238,499			288,522
Transfer of investment securities from AFS to HTM	[1],[2]				21,522	$ 0
Debt securities available-for-sale (AFS)
Investment Holdings
Total investments		238,499	238,499		238,499			288,522
Debt securities held-to-maturity (HTM)
Investment Holdings
Total investments		267,592	267,592		267,592			216,963
Non-marketable securities measured using measurement alternative
Investment Holdings
Total investments		1,670	1,670		1,670			1,413
Mortgage-backed securities - U.S. government-sponsored agency guaranteed
Debt securities AFS
Amortized cost		12,982	12,982		12,982			33,064
Gross unrealized gains		25	25		25			453
Gross unrealized losses		492	492		492			301
Allowance for credit losses		0	0		0			0
Fair value		12,515	12,515		12,515			33,216
Transfer of investment securities from AFS to HTM		21,500
Securities transferred from AFS to HTM, unrealized loss position		2,300	2,300		2,300
Mortgage-backed securities - Non-U.S. residential
Debt securities AFS
Amortized cost		281	281		281			380
Gross unrealized gains		0	0		0			1
Gross unrealized losses		3	3		3			1
Allowance for credit losses		0	0		0			0
Fair value		278	278		278			380
Commercial
Debt securities AFS
Amortized cost		7	7		7			25
Gross unrealized gains		0	0		0			0
Gross unrealized losses		0	0		0			0
Allowance for credit losses		0	0		0			0
Fair value		7	7		7			25
Mortgage-backed securities
Debt securities AFS
Amortized cost		13,270	13,270		13,270			33,469
Gross unrealized gains		25	25		25			454
Gross unrealized losses		495	495		495			302
Allowance for credit losses		0	0		0			0
Fair value		12,800	12,800		12,800			33,621
U.S. Treasury
Debt securities AFS
Amortized cost		94,740	94,740		94,740			122,669
Gross unrealized gains		42	42		42			615
Gross unrealized losses		2,918	2,918		2,918			844
Allowance for credit losses		0	0		0			0
Fair value		91,864	91,864		91,864			122,440
Agency obligations
Debt securities AFS
Amortized cost		0	0		0			0
Gross unrealized gains		0	0		0			0
Gross unrealized losses		0	0		0			0
Allowance for credit losses		0	0		0			0
Fair value		0	0		0			0
U.S. Treasury and federal agency securities
Debt securities AFS
Amortized cost		94,740	94,740		94,740			122,669
Gross unrealized gains		42	42		42			615
Gross unrealized losses		2,918	2,918		2,918			844
Allowance for credit losses		0	0		0			0
Fair value		91,864	91,864		91,864			122,440
State and municipal
Debt securities AFS
Amortized cost		2,677	2,677		2,677			2,643
Gross unrealized gains		16	16		16			79
Gross unrealized losses		201	201		201			101
Allowance for credit losses		0	0		0			0
Fair value		2,492	2,492		2,492			2,621
Foreign government
Debt securities AFS
Amortized cost		122,184	122,184		122,184			119,426
Gross unrealized gains		424	424		424			337
Gross unrealized losses		2,922	2,922		2,922			1,023
Allowance for credit losses		0	0		0			0
Fair value		119,686	119,686		119,686			118,740
Corporate
Debt securities AFS
Amortized cost		6,646	6,646		6,646			5,972
Gross unrealized gains		19	19		19			33
Gross unrealized losses		214	214		214			77
Allowance for credit losses		6	6		6			8
Fair value		6,445	6,445		6,445			5,920
Asset-backed securities
Debt securities AFS
Amortized cost		275	275		275			304
Gross unrealized gains		2	2		2			0
Gross unrealized losses		1	1		1			1
Allowance for credit losses		0	0		0			0
Fair value		276	276		276			303
Other debt securities
Debt securities AFS
Amortized cost		4,948	4,948		4,948			4,880
Gross unrealized gains		0	0		0			1
Gross unrealized losses		12	12		12			4
Allowance for credit losses		0	0		0			0
Fair value		4,936	4,936		4,936			4,877
Debt securities AFS
Debt securities AFS
Amortized cost		244,740	244,740		244,740			289,363
Gross unrealized gains		528	528		528			1,519
Gross unrealized losses		6,763	6,763		6,763			2,352
Allowance for credit losses		6	6		6			8
Fair value		238,499	238,499		238,499			288,522
Fair value | Marketable equity securities carried at fair value
Investment Holdings
Total investments		588	588		588			543
Fair value | Non-marketable equity securities
Investment Holdings
Total investments		458	458		458			489
Carried at cost | Non-marketable equity securities
Investment Holdings
Total investments		$ 5,071	$ 5,071		$ 5,071			$ 4,892

[1] Operating and finance lease right-of-use assets and lease liabilities represent non-cash investing and financing activities, respectively, and are not included in the non-cash investing activities presented here. See Note 22 for more information and balances as of June 30, 2022.

[2] See Note 2 for further information on significant disposals.