BENEFITS PAYABLE - Activity in Benefits Payable (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Balances at January 1	$ 4,976	$ 4,475	$ 3,893
Provision for premium deficiency	(176)	0	0
Less: Reinsurance recoverables	(85)	(78)	0
Balances at January 1, net	4,487	4,715	4,397	$ 3,893
Current year, Incurred	45,318	44,397	38,641
Prior years, Incurred	(582)	(236)	(518)
Total incurred	44,736	44,161	38,123
Current year, Paid	(40,852)	(39,802)	(34,357)
Prior years, Paid	(4,112)	(4,041)	(3,262)
Total paid	(44,964)	(43,843)	(37,619)
Provision for premium deficiency	0	176	0
Reinsurance recoverable	76	85	78
Balances at December 31	4,563	4,976	4,475
Retail
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Balances at January 1	4,296	3,879	3,268
Provision for premium deficiency	(176)	0	0
Less: Reinsurance recoverables	(85)	(78)	0
Balances at January 1, net		4,035	3,801	3,268
Current year, Incurred	40,854	39,760	33,996
Prior years, Incurred	(535)	(228)	(488)
Total incurred	40,319	39,532	33,508
Current year, Paid	(36,967)	(35,835)	(30,305)
Prior years, Paid	(3,487)	(3,463)	(2,670)
Total paid	(40,454)	(39,298)	(32,975)
Provision for premium deficiency	0	176	0
Reinsurance recoverable	76	85	78
Balances at December 31	3,976	4,296	3,879
Group
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Balances at January 1	600	578	577
Less: Reinsurance recoverables	0	0	0
Balances at January 1, net		600	578	$ 577
Current year, Incurred	5,160	5,261	5,148
Prior years, Incurred	(46)	(7)	(29)
Total incurred	5,114	5,254	5,119
Current year, Paid	(4,605)	(4,671)	(4,574)
Prior years, Paid	(546)	(561)	(544)
Total paid	(5,151)	(5,232)	(5,118)
Reinsurance recoverable	0	0	0
Balances at December 31	$ 563	$ 600	$ 578