GOODWILL AND OTHER INTANGIBLES (Goodwill) (Details) - USD ($)		3 Months Ended		9 Months Ended
	Jan. 01, 2019	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Goodwill [Roll Forward]
Goodwill		$ 2,596,161,000		$ 2,596,161,000		$ 4,444,389,000
Impairment during the period	$ 0	0	$ 0	(1,848,228,000)	$ 0
CBB
Goodwill [Roll Forward]
Goodwill		322,920,000		322,920,000		1,880,304,000
Impairment during the period				(1,557,384,000)
C&I
Goodwill [Roll Forward]
Goodwill		27,080,000		27,080,000		317,924,000
Impairment during the period				(290,844,000)
CRE & VF
Goodwill [Roll Forward]
Goodwill		1,095,071,000		1,095,071,000		1,095,071,000
Impairment during the period				0
CIB
Goodwill [Roll Forward]
Goodwill		131,130,000		131,130,000		131,130,000
Impairment during the period				0
SC
Goodwill [Roll Forward]
Goodwill		$ 1,019,960,000		1,019,960,000		$ 1,019,960,000
Impairment during the period				$ 0