BASIS OF PRESENTATION AND ACCOUNTING CHANGES - Accounting Changes (Details) - USD ($) $ in Millions	Sep. 30, 2015	Jul. 01, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014
New Accounting Pronouncements or Change in Accounting Principle
Addition (reduction) in Retained earnings	$ 130,921				$ 117,852
Other assets	$ 132,832				122,122
Accounting Standards Update 2014-01
New Accounting Pronouncements or Change in Accounting Principle
Addition (reduction) in Retained earnings				$ (349)
Other assets				(178)
Addition (reduction) in deferred tax assets				$ (171)
New Accounting Pronouncement, Early Adoption, Effect | Accounting Standards Update 2015-03
New Accounting Pronouncements or Change in Accounting Principle
Reclassification of debt issuance costs		$ 150
New Accounting Pronouncement, Early Adoption, Effect | Accounting Standards Update 2015-07
New Accounting Pronouncements or Change in Accounting Principle
Reduction in level 3 assets			$ (1,000)		$ (1,100)