DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES - Notional Amounts and Gross Fair Values (Detail) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Derivatives, Fair Value [Line Items]
Notional amount	$ 7,476.0	$ 6,942.0
Derivative asset, not offset against collateral	1.0	2.0
Derivative liability, not offset against collateral	17.0	13.0
Derivative asset, not subject to master netting arrangement	74.0	41.0
Derivative liability, not subject to master netting arrangement	13.0	26.0
Fair value, asset	75.0	43.0
Fair value, liability	30.0	39.0
Interest rate contracts - designated [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, not offset against collateral	0.0	0.0
Derivative liability, not offset against collateral	1.0	3.0
Interest rate swaps - not designated [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, not offset against collateral	1.0	2.0
Derivative liability, not offset against collateral	16.0	10.0
Derivative asset, not subject to master netting arrangement	72.0	40.0
Derivative liability, not subject to master netting arrangement	12.0	26.0
Equity contracts - not designated [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, not offset against collateral	0.0	0.0
Derivative liability, not offset against collateral	0.0	0.0
Derivative asset, not subject to master netting arrangement	0.0	0.0
Derivative liability, not subject to master netting arrangement	0.0	0.0
Interest rate lock commitments – not designated [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, not subject to master netting arrangement	2.0	1.0
Derivative liability, not subject to master netting arrangement	0.0	0.0
Forward delivery commitments – not designated [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, not subject to master netting arrangement	0.0	0.0
Derivative liability, not subject to master netting arrangement	1.0	0.0
Credit risk contracts - not designated [Member]
Derivatives, Fair Value [Line Items]
Notional amount	138.5
Derivative asset, not subject to master netting arrangement	0.0	0.0
Derivative liability, not subject to master netting arrangement	0.0	0.0
Subject to Master Netting Arrangements [Member]
Derivatives, Fair Value [Line Items]
Notional amount	4,172.0	3,896.0
Subject to Master Netting Arrangements [Member] \| Interest rate contracts - designated [Member]
Derivatives, Fair Value [Line Items]
Notional amount	1,255.0	1,155.0
Subject to Master Netting Arrangements [Member] \| Interest rate swaps - not designated [Member]
Derivatives, Fair Value [Line Items]
Notional amount	2,917.0	2,740.0
Subject to Master Netting Arrangements [Member] \| Equity contracts - not designated [Member]
Derivatives, Fair Value [Line Items]
Notional amount	0.0	1.0
Not Subject to Master Netting Arrangements [Member]
Derivatives, Fair Value [Line Items]
Notional amount	3,304.0	3,046.0
Not Subject to Master Netting Arrangements [Member] \| Interest rate swaps - not designated [Member]
Derivatives, Fair Value [Line Items]
Notional amount	2,917.0	2,740.0
Not Subject to Master Netting Arrangements [Member] \| Equity contracts - not designated [Member]
Derivatives, Fair Value [Line Items]
Notional amount	0.0	1.0
Not Subject to Master Netting Arrangements [Member] \| Interest rate lock commitments – not designated [Member]
Derivatives, Fair Value [Line Items]
Notional amount	83.0	47.0
Not Subject to Master Netting Arrangements [Member] \| Forward delivery commitments – not designated [Member]
Derivatives, Fair Value [Line Items]
Notional amount	101.0	55.0
Not Subject to Master Netting Arrangements [Member] \| Credit risk contracts - not designated [Member]
Derivatives, Fair Value [Line Items]
Notional amount	$ 203.0	$ 203.0

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

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