BASIS OF PRESENTATION AND ACCOUNTING CHANGES - Accounting Changes (Details) - USD ($) $ in Millions		Jun. 30, 2017	Mar. 31, 2017	Jan. 01, 2017	Dec. 31, 2016	Jun. 30, 2016	Mar. 31, 2016	Jan. 01, 2016	Dec. 31, 2015
New Accounting Pronouncements or Change in Accounting Principle
Net reduction to total stockholders' equity		$ (231,107)			$ (226,143)	$ (233,021)
Reclassification from AOCI		29,899			32,381
Increase (decrease) in retained earnings		152,178			146,477
Increase in assets		1,864,063			1,792,077
Increase in liabilities		1,632,956			1,565,934
Accounting Standards Update 2016-01
New Accounting Pronouncements or Change in Accounting Principle
Reclassification from AOCI								$ 15
Increase (decrease) in retained earnings								$ 15
Pro Forma | Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle
Increase (decrease) in retained earnings		200
Increase in assets		5,000
Increase in liabilities		5,000
Pro Forma | Accounting Standards Update 2016-16
New Accounting Pronouncements or Change in Accounting Principle
Increase in DTAs		500
Decrease in prepaid taxes		500
Early adoption | Accounting Standards Update 2017-08
New Accounting Pronouncements or Change in Accounting Principle
Net reduction to total stockholders' equity				$ 156
Retained earnings
New Accounting Pronouncements or Change in Accounting Principle
Net reduction to total stockholders' equity		(152,178)			(146,477)	(140,527)			$ (133,841)
Cumulative effect adjustment after tax	[1]				(660)				15
Retained earnings | Early adoption | Accounting Standards Update 2017-08
New Accounting Pronouncements or Change in Accounting Principle
Cumulative effect adjustment after tax				(660)
Accumulated other comprehensive income (loss)
New Accounting Pronouncements or Change in Accounting Principle
Net reduction to total stockholders' equity		$ 29,899	$ 30,413		32,381	$ 26,115	$ 26,626		29,344
Cumulative effect adjustment after tax	[1]				$ 504				$ (15)
Accumulated other comprehensive income (loss) | Early adoption | Accounting Standards Update 2017-08
New Accounting Pronouncements or Change in Accounting Principle
Cumulative effect adjustment after tax				$ 504

[1] See Note 1 to the Consolidated Financial Statements for additional details.