INCOME TAXES - Tax Credit Carryforward and Expiration Dates (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Operating Loss and Tax Carryforwards
Net DFA	$ 23,094	$ 22,903
U.S. Federal and New York State and City NOL carryforward period	20 years
U.S. foreign tax credit carryforward period (in years)	10 years
Limit on utilization of foreign tax credit carryforwards (as percent)	21.00%
Domestic losses allowed to be reclassified as foreign source income	$ 39,000
Foreign
Operating Loss and Tax Carryforwards
Operating loss carryforward	1,500	2,000
Net DFA	2,100	2,200
U.S. federal
Operating Loss and Tax Carryforwards
Tax credit carryforward	2,500	1,000
Operating loss carryforward	13,500	12,500
U.S. federal
Operating Loss and Tax Carryforwards
Net DFA	17,800	17,100
Foreign tax credits (FTCs)	6,300	6,800
Gross foreign tax credits	10,900
2027 | U.S. federal
Operating Loss and Tax Carryforwards
Operating loss carryforward	100	200
2028 | U.S. federal
Operating Loss and Tax Carryforwards
Operating loss carryforward	100	100
2030 | U.S. federal
Operating Loss and Tax Carryforwards
Operating loss carryforward	300	300
2032 | U.S. federal
Operating Loss and Tax Carryforwards
Operating loss carryforward	0	100
2033 | U.S. federal
Operating Loss and Tax Carryforwards
Tax credit carryforward	300	0
Operating loss carryforward	1,600	1,600
2034 | U.S. federal
Operating Loss and Tax Carryforwards
Tax credit carryforward	200	0
Operating loss carryforward	2,000	2,100
2034 | New York State Tax Authority
Operating Loss and Tax Carryforwards
Operating loss carryforward	9,900	11,700
2034 | New York City tax authority
Operating Loss and Tax Carryforwards
Operating loss carryforward	10,000	11,500
2035 | U.S. federal
Operating Loss and Tax Carryforwards
Tax credit carryforward	200	0
Operating loss carryforward	3,300	3,300
2036 | U.S. federal
Operating Loss and Tax Carryforwards
Tax credit carryforward	100	100
Operating loss carryforward	2,100	2,100
2037 | U.S. federal
Operating Loss and Tax Carryforwards
Tax credit carryforward	500	400
Operating loss carryforward	1,000	1,000
2038 | U.S. federal
Operating Loss and Tax Carryforwards
Tax credit carryforward	500	500
2039 | U.S. federal
Operating Loss and Tax Carryforwards
Tax credit carryforward	700	0
Unlimited Carry-Forward Period | U.S. federal
Operating Loss and Tax Carryforwards
Operating loss carryforward	$ 3,000	1,700
Minimum
Operating Loss and Tax Carryforwards
Limit on domestic losses to be reclassified as foreign source income (as a percent)	50.00%
Maximum
Operating Loss and Tax Carryforwards
Limit on domestic losses to be reclassified as foreign source income (as a percent)	100.00%
General Basket | Foreign
Operating Loss and Tax Carryforwards
Tax credit carryforward	$ 7,400	8,400
General Basket | 2020 | Foreign
Operating Loss and Tax Carryforwards
Tax credit carryforward	900	2,000
General Basket | 2021 | Foreign
Operating Loss and Tax Carryforwards
Tax credit carryforward	1,100	1,100
General Basket | 2022 | Foreign
Operating Loss and Tax Carryforwards
Tax credit carryforward	2,400	2,400
General Basket | 2023 | Foreign
Operating Loss and Tax Carryforwards
Tax credit carryforward	400	400
General Basket | 2025 | Foreign
Operating Loss and Tax Carryforwards
Tax credit carryforward	1,400	1,400
General Basket | 2027 | Foreign
Operating Loss and Tax Carryforwards
Tax credit carryforward	1,200	1,100
Branch Basket | Foreign
Operating Loss and Tax Carryforwards
Tax credit carryforward	3,500	4,400
Branch Basket | 2019 | Foreign
Operating Loss and Tax Carryforwards
Tax credit carryforward	0	900
Branch Basket | 2020 | Foreign
Operating Loss and Tax Carryforwards
Tax credit carryforward	700	600
Branch Basket | 2021 | Foreign
Operating Loss and Tax Carryforwards
Tax credit carryforward	600	700
Branch Basket | 2022 | Foreign
Operating Loss and Tax Carryforwards
Tax credit carryforward	1,000	900
Branch Basket | 2028 | Foreign
Operating Loss and Tax Carryforwards
Tax credit carryforward	900	1,300
Branch Basket | 2029 | Foreign
Operating Loss and Tax Carryforwards
Tax credit carryforward	$ 300	$ 0