GUARANTOR FINANCIAL INFORMATION - Condensed Consolidating Statement of Cash Flows (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Cash flows – operating activities
Cash from (used for) operating activities - continuing operations	$ 4,008	$ 3,846
Cash from (used for) operating activities - discontinued operations	(490)	(5,719)
Cash from (used for) operating activities	3,518	(1,873)
Cash flows – investing activities
Cash from (used for) investing activities – continuing operations	4,692	53,559
Cash from (used for) investing activities – continuing operations	(2,349)	(12,056)
Cash from (used for) investing activities	2,343	41,503
Cash flows – financing activities
Cash from (used for) financing activities – continuing operations	(18,228)	(75,188)
Cash from (used for) financing activities – discontinued operations	1,905	295
Cash from (used for) financing activities	(16,323)	(74,893)
Effect of currency exchange rate changes on cash and equivalents	1,253	(169)
Increase (decrease) in cash and equivalents	(9,208)	(35,432)
Cash and equivalents at beginning of year	49,558	90,878
Cash and equivalents at September 30	40,350	55,445
Less cash and equivalents of discontinued operations at September 30	496	2,915
Cash and equivalents of continuing operations at September 30	39,854	52,530
Reportable Legal Entities
Cash flows – operating activities
Cash from (used for) operating activities - continuing operations	6,103	20,245
Cash flows – investing activities
Cash from (used for) investing activities – continuing operations	752	47,548
Cash flows – financing activities
Cash from (used for) financing activities – continuing operations	(16,383)	(85,578)
Reportable Legal Entities | Parent Company Guarantor
Cash flows – operating activities
Cash from (used for) operating activities - continuing operations	(25,937)	(14,847)
Cash from (used for) operating activities - discontinued operations	(501)	(954)
Cash from (used for) operating activities	(26,437)	(15,801)
Cash flows – investing activities
Cash from (used for) investing activities – continuing operations	(1,723)	20,902
Cash from (used for) investing activities – continuing operations	0	0
Cash from (used for) investing activities	(1,723)	20,902
Cash flows – financing activities
Cash from (used for) financing activities – continuing operations	26,339	(6,894)
Cash from (used for) financing activities – discontinued operations	0	0
Cash from (used for) financing activities	26,339	(6,894)
Effect of currency exchange rate changes on cash and equivalents	0	0
Increase (decrease) in cash and equivalents	(1,821)	(1,792)
Cash and equivalents at beginning of year	2,558	4,137
Cash and equivalents at September 30	737	2,344
Less cash and equivalents of discontinued operations at September 30	0	0
Cash and equivalents of continuing operations at September 30	737	2,344
Reportable Legal Entities | Subsidiary Issuer
Cash flows – operating activities
Cash from (used for) operating activities - continuing operations	39	175
Cash from (used for) operating activities - discontinued operations	0	0
Cash from (used for) operating activities	39	175
Cash flows – investing activities
Cash from (used for) investing activities – continuing operations	(39)	16,080
Cash from (used for) investing activities – continuing operations	0	0
Cash from (used for) investing activities	(39)	16,080
Cash flows – financing activities
Cash from (used for) financing activities – continuing operations	0	(16,255)
Cash from (used for) financing activities – discontinued operations	0	0
Cash from (used for) financing activities	0	(16,255)
Effect of currency exchange rate changes on cash and equivalents	0	0
Increase (decrease) in cash and equivalents	0	0
Cash and equivalents at beginning of year	0	0
Cash and equivalents at September 30	0	0
Less cash and equivalents of discontinued operations at September 30	0	0
Cash and equivalents of continuing operations at September 30	0	0
Reportable Legal Entities | Subsidiary Guarantor
Cash flows – operating activities
Cash from (used for) operating activities - continuing operations	(81)	(121)
Cash from (used for) operating activities - discontinued operations	0	0
Cash from (used for) operating activities	(81)	(121)
Cash flows – investing activities
Cash from (used for) investing activities – continuing operations	345	36,317
Cash from (used for) investing activities – continuing operations	0	0
Cash from (used for) investing activities	345	36,317
Cash flows – financing activities
Cash from (used for) financing activities – continuing operations	(265)	(36,194)
Cash from (used for) financing activities – discontinued operations	0	0
Cash from (used for) financing activities	(265)	(36,194)
Effect of currency exchange rate changes on cash and equivalents	0	0
Increase (decrease) in cash and equivalents	0	3
Cash and equivalents at beginning of year	3	0
Cash and equivalents at September 30	3	3
Less cash and equivalents of discontinued operations at September 30	0	0
Cash and equivalents of continuing operations at September 30	3	3
Reportable Legal Entities | Non- Guarantor Subsidiaries
Cash flows – operating activities
Cash from (used for) operating activities - continuing operations	193,403	83,404
Cash from (used for) operating activities - discontinued operations	8	(4,366)
Cash from (used for) operating activities	193,411	79,038
Cash flows – investing activities
Cash from (used for) investing activities – continuing operations	(257,130)	32,000
Cash from (used for) investing activities – continuing operations	(2,349)	(12,056)
Cash from (used for) investing activities	(259,479)	19,944
Cash flows – financing activities
Cash from (used for) financing activities – continuing operations	104,160	(150,446)
Cash from (used for) financing activities – discontinued operations	1,905	295
Cash from (used for) financing activities	106,065	(150,151)
Effect of currency exchange rate changes on cash and equivalents	1,253	(169)
Increase (decrease) in cash and equivalents	41,251	(51,339)
Cash and equivalents at beginning of year	(1,132)	107,350
Cash and equivalents at September 30	40,119	56,011
Less cash and equivalents of discontinued operations at September 30	496	2,915
Cash and equivalents of continuing operations at September 30	39,623	53,095
Consolidating Adjustments
Cash flows – operating activities
Cash from (used for) operating activities - continuing operations	(163,416)	(64,766)
Cash from (used for) operating activities - discontinued operations	3	(399)
Cash from (used for) operating activities	(163,413)	(65,165)
Cash flows – investing activities
Cash from (used for) investing activities – continuing operations	263,239	(51,740)
Cash from (used for) investing activities – continuing operations	0	0
Cash from (used for) investing activities	263,239	(51,740)
Cash flows – financing activities
Cash from (used for) financing activities – continuing operations	(148,463)	134,601
Cash from (used for) financing activities – discontinued operations	0	0
Cash from (used for) financing activities	(148,463)	134,601
Effect of currency exchange rate changes on cash and equivalents	0	0
Increase (decrease) in cash and equivalents	(48,638)	17,696
Cash and equivalents at beginning of year	48,129	(20,609)
Cash and equivalents at September 30	(509)	(2,913)
Less cash and equivalents of discontinued operations at September 30	0	0
Cash and equivalents of continuing operations at September 30	$ (509)	$ (2,913)