DERIVATIVES ACTIVITIES - Derivative Notionals (Details) - USD ($)	Jun. 30, 2018	Dec. 31, 2017
Net Investment Hedging
Derivatives
Derivative notionals		$ 2,000,000
Hedging instruments under ASC 815
Derivatives
Derivative notionals	$ 322,463,000,000	270,445,000,000
Hedging instruments under ASC 815 | Interest rate contracts
Derivatives
Derivative notionals	222,057,000,000	189,779,000,000
Hedging instruments under ASC 815 | Interest rate swaps
Derivatives
Derivative notionals	222,057,000,000	189,779,000,000
Hedging instruments under ASC 815 | Interest rate futures and forwards
Derivatives
Derivative notionals	0	0
Hedging instruments under ASC 815 | Interest rate contract options | Written or Sold
Derivatives
Derivative notionals	0	0
Hedging instruments under ASC 815 | Interest rate contract options | Purchased
Derivatives
Derivative notionals	0	0
Hedging instruments under ASC 815 | Foreign exchange contracts
Derivatives
Derivative notionals	100,293,000,000	80,643,000,000
Hedging instruments under ASC 815 | Foreign exchange swaps
Derivatives
Derivative notionals	56,971,000,000	37,162,000,000
Hedging instruments under ASC 815 | Foreign exchange futures, forwards and spot
Derivatives
Derivative notionals	37,911,000,000	33,103,000,000
Hedging instruments under ASC 815 | Foreign exchange contract options | Written or Sold
Derivatives
Derivative notionals	2,503,000,000	3,951,000,000
Hedging instruments under ASC 815 | Foreign exchange contract options | Purchased
Derivatives
Derivative notionals	2,908,000,000	6,427,000,000
Hedging instruments under ASC 815 | Equity contracts
Derivatives
Derivative notionals	0	0
Hedging instruments under ASC 815 | Equity swaps
Derivatives
Derivative notionals	0	0
Hedging instruments under ASC 815 | Equity futures and forwards
Derivatives
Derivative notionals	0	0
Hedging instruments under ASC 815 | Equity contract options | Written or Sold
Derivatives
Derivative notionals	0	0
Hedging instruments under ASC 815 | Equity contract options | Purchased
Derivatives
Derivative notionals	0	0
Hedging instruments under ASC 815 | Commodity and other contracts
Derivatives
Derivative notionals	113,000,000	23,000,000
Hedging instruments under ASC 815 | Commodity and other swaps
Derivatives
Derivative notionals	0	0
Hedging instruments under ASC 815 | Commodity and other futures and forwards
Derivatives
Derivative notionals	113,000,000	23,000,000
Hedging instruments under ASC 815 | Commodity and other contracts | Written or Sold
Derivatives
Derivative notionals	0	0
Hedging instruments under ASC 815 | Commodity and other contracts | Purchased
Derivatives
Derivative notionals	0	0
Hedging instruments under ASC 815 | Credit derivatives
Derivatives
Derivative notionals	0	0
Hedging instruments under ASC 815 | Credit derivatives | Written or Sold
Derivatives
Derivative notionals	0	0
Hedging instruments under ASC 815 | Credit derivatives | Purchased
Derivatives
Derivative notionals	0	0
Other derivative instruments, Trading derivatives
Derivatives
Derivative notionals	55,853,435,000,000	45,792,663,000,000
Other derivative instruments, Trading derivatives | Interest rate contracts
Derivatives
Derivative notionals	37,043,611,000,000	31,964,914,000,000
Other derivative instruments, Trading derivatives | Interest rate swaps
Derivatives
Derivative notionals	20,721,169,000,000	18,754,219,000,000
Other derivative instruments, Trading derivatives | Interest rate futures and forwards
Derivatives
Derivative notionals	8,073,755,000,000	6,460,539,000,000
Other derivative instruments, Trading derivatives | Interest rate contract options | Written or Sold
Derivatives
Derivative notionals	4,391,594,000,000	3,516,131,000,000
Other derivative instruments, Trading derivatives | Interest rate contract options | Purchased
Derivatives
Derivative notionals	3,857,093,000,000	3,234,025,000,000
Other derivative instruments, Trading derivatives | Foreign exchange contracts
Derivatives
Derivative notionals	15,903,616,000,000	10,950,471,000,000
Other derivative instruments, Trading derivatives | Foreign exchange swaps
Derivatives
Derivative notionals	7,020,783,000,000	5,576,357,000,000
Other derivative instruments, Trading derivatives | Foreign exchange futures, forwards and spot
Derivatives
Derivative notionals	5,424,415,000,000	3,097,700,000,000
Other derivative instruments, Trading derivatives | Foreign exchange contract options | Written or Sold
Derivatives
Derivative notionals	1,738,131,000,000	1,127,728,000,000
Other derivative instruments, Trading derivatives | Foreign exchange contract options | Purchased
Derivatives
Derivative notionals	1,720,287,000,000	1,148,686,000,000
Other derivative instruments, Trading derivatives | Equity contracts
Derivatives
Derivative notionals	1,038,776,000,000	1,006,565,000,000
Other derivative instruments, Trading derivatives | Equity swaps
Derivatives
Derivative notionals	253,135,000,000	215,834,000,000
Other derivative instruments, Trading derivatives | Equity futures and forwards
Derivatives
Derivative notionals	56,968,000,000	72,616,000,000
Other derivative instruments, Trading derivatives | Equity contract options | Written or Sold
Derivatives
Derivative notionals	410,955,000,000	389,961,000,000
Other derivative instruments, Trading derivatives | Equity contract options | Purchased
Derivatives
Derivative notionals	317,718,000,000	328,154,000,000
Other derivative instruments, Trading derivatives | Commodity and other contracts
Derivatives
Derivative notionals	413,966,000,000	357,858,000,000
Other derivative instruments, Trading derivatives | Commodity and other swaps
Derivatives
Derivative notionals	106,646,000,000	82,039,000,000
Other derivative instruments, Trading derivatives | Commodity and other futures and forwards
Derivatives
Derivative notionals	163,593,000,000	153,248,000,000
Other derivative instruments, Trading derivatives | Commodity and other contracts | Written or Sold
Derivatives
Derivative notionals	72,359,000,000	62,045,000,000
Other derivative instruments, Trading derivatives | Commodity and other contracts | Purchased
Derivatives
Derivative notionals	71,368,000,000	60,526,000,000
Other derivative instruments, Trading derivatives | Credit derivatives
Derivatives
Derivative notionals	1,453,466,000,000	1,512,855,000,000
Other derivative instruments, Trading derivatives | Credit derivatives | Written or Sold
Derivatives
Derivative notionals	703,904,000,000	735,142,000,000
Other derivative instruments, Trading derivatives | Credit derivatives | Purchased
Derivatives
Derivative notionals	$ 749,562,000,000	$ 777,713,000,000