GUARANTOR FINANCIAL INFORMATION - Condensed Consolidating Statement of Cash Flows (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Cash flows – operating activities
Cash from (used for) operating activities - continuing operations	$ 3,389	$ 2,014
Cash from (used for) operating activities - discontinued operations	(895)	(4,849)
Cash from (used for) operating activities	2,494	(2,835)
Cash flows – investing activities
Cash from (used for) investing activities – continuing operations	4,083	42,414
Cash from (used for) investing activities – continuing operations	(1,922)	(10,646)
Cash from (used for) investing activities	2,161	31,768
Cash flows – financing activities
Cash from (used for) financing activities – continuing operations	(12,089)	(62,763)
Cash from (used for) financing activities – discontinued operations	1,909	(711)
Cash from (used for) financing activities	(10,181)	(63,474)
Effect of currency exchange rate changes on cash and equivalents	538	(24)
Increase (decrease) in cash and equivalents	(4,988)	(34,565)
Cash and equivalents at beginning of year	49,558	90,878
Cash and equivalents at June 30	44,571	56,313
Less cash and equivalents of discontinued operations at June 30	522	4,190
Cash and equivalents of continuing operations at June 30	44,049	52,123
Reportable Legal Entities
Cash flows – operating activities
Cash from (used for) operating activities - continuing operations	5,549	11,207
Cash flows – investing activities
Cash from (used for) investing activities – continuing operations	3,173	39,495
Cash flows – financing activities
Cash from (used for) financing activities – continuing operations	(13,339)	(69,038)
Reportable Legal Entities | Parent Company Guarantor
Cash flows – operating activities
Cash from (used for) operating activities - continuing operations	12,674	(21,014)
Cash from (used for) operating activities - discontinued operations	(388)	(849)
Cash from (used for) operating activities	12,286	(21,863)
Cash flows – investing activities
Cash from (used for) investing activities – continuing operations	(26,871)	17,416
Cash from (used for) investing activities – continuing operations	0	0
Cash from (used for) investing activities	(26,871)	17,416
Cash flows – financing activities
Cash from (used for) financing activities – continuing operations	16,446	3,174
Cash from (used for) financing activities – discontinued operations	0	0
Cash from (used for) financing activities	16,446	3,174
Effect of currency exchange rate changes on cash and equivalents	0	0
Increase (decrease) in cash and equivalents	1,861	(1,274)
Cash and equivalents at beginning of year	2,558	4,137
Cash and equivalents at June 30	4,420	2,863
Less cash and equivalents of discontinued operations at June 30	0	0
Cash and equivalents of continuing operations at June 30	4,420	2,863
Reportable Legal Entities | Subsidiary Issuer
Cash flows – operating activities
Cash from (used for) operating activities - continuing operations	25	182
Cash from (used for) operating activities - discontinued operations	0	0
Cash from (used for) operating activities	25	182
Cash flows – investing activities
Cash from (used for) investing activities – continuing operations	(25)	16,084
Cash from (used for) investing activities – continuing operations	0	0
Cash from (used for) investing activities	(25)	16,084
Cash flows – financing activities
Cash from (used for) financing activities – continuing operations	0	(16,265)
Cash from (used for) financing activities – discontinued operations	0	0
Cash from (used for) financing activities	0	(16,265)
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 June 30	0	0
Less cash and equivalents of discontinued operations at June 30	0	0
Cash and equivalents of continuing operations at June 30	0	0
Reportable Legal Entities | Subsidiary Guarantor
Cash flows – operating activities
Cash from (used for) operating activities - continuing operations	225	1,032
Cash from (used for) operating activities - discontinued operations	0	(996)
Cash from (used for) operating activities	225	37
Cash flows – investing activities
Cash from (used for) investing activities – continuing operations	608	7,995
Cash from (used for) investing activities – continuing operations	0	0
Cash from (used for) investing activities	608	7,995
Cash flows – financing activities
Cash from (used for) financing activities – continuing operations	(833)	(7,995)
Cash from (used for) financing activities – discontinued operations	0	0
Cash from (used for) financing activities	(833)	(7,995)
Effect of currency exchange rate changes on cash and equivalents	0	0
Increase (decrease) in cash and equivalents	0	37
Cash and equivalents at beginning of year	3	0
Cash and equivalents at June 30	3	37
Less cash and equivalents of discontinued operations at June 30	0	0
Cash and equivalents of continuing operations at June 30	3	37
Reportable Legal Entities | Non- Guarantor Subsidiaries
Cash flows – operating activities
Cash from (used for) operating activities - continuing operations	113,799	10,275
Cash from (used for) operating activities - discontinued operations	(507)	(3,826)
Cash from (used for) operating activities	113,292	6,449
Cash flows – investing activities
Cash from (used for) investing activities – continuing operations	(60,997)	97,631
Cash from (used for) investing activities – continuing operations	(1,922)	(10,646)
Cash from (used for) investing activities	(62,919)	86,985
Cash flows – financing activities
Cash from (used for) financing activities – continuing operations	(60,547)	(142,451)
Cash from (used for) financing activities – discontinued operations	1,909	(711)
Cash from (used for) financing activities	(58,639)	(143,162)
Effect of currency exchange rate changes on cash and equivalents	538	(24)
Increase (decrease) in cash and equivalents	(7,728)	(49,752)
Cash and equivalents at beginning of year	48,423	107,350
Cash and equivalents at June 30	40,696	57,598
Less cash and equivalents of discontinued operations at June 30	522	4,190
Cash and equivalents of continuing operations at June 30	40,174	53,408
Consolidating Adjustments
Cash flows – operating activities
Cash from (used for) operating activities - continuing operations	(123,335)	11,539
Cash from (used for) operating activities - discontinued operations	0	821
Cash from (used for) operating activities	(123,335)	12,361
Cash flows – investing activities
Cash from (used for) investing activities – continuing operations	91,369	(96,712)
Cash from (used for) investing activities – continuing operations	0	0
Cash from (used for) investing activities	91,369	(96,712)
Cash flows – financing activities
Cash from (used for) financing activities – continuing operations	32,845	100,775
Cash from (used for) financing activities – discontinued operations	0	0
Cash from (used for) financing activities	32,845	100,775
Effect of currency exchange rate changes on cash and equivalents	0	0
Increase (decrease) in cash and equivalents	879	16,424
Cash and equivalents at beginning of year	(1,426)	(20,609)
Cash and equivalents at June 30	(547)	(4,185)
Less cash and equivalents of discontinued operations at June 30	0	0
Cash and equivalents of continuing operations at June 30	$ (547)	$ (4,185)