Guarantor and Non-Guarantor Condensed Consolidating Financial Statements (Condensed Consolidating Statement of Operations and Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Condensed Financial Statements, Captions [Line Items]
Total revenues	$ 2,692	$ 2,830	$ 5,145	$ 5,366
Expenses:
Direct operating	1,505	1,594	2,913	3,037
Depreciation of revenue earning equipment and lease charges, net	696	708	1,403	1,434
Selling, general and administrative	296	265	560	541
Interest expense, net	155	162	308	315
Other (income) expense, net	(10)	(22)	(4)	(25)
Total expenses	2,642	2,707	5,180	5,302
Income (loss) before income taxes	50	123	(35)	64
Provision for taxes on income	(27)	(50)	(11)	(58)
Equity in earnings (losses) of subsidiaries, net of tax	0	0	0	0
Net income (loss)	23	73	(46)	6
Other comprehensive income (loss), net of tax	11	12	(35)	(6)
Total comprehensive income (loss)	34	85	(81)	0
Eliminations
Condensed Financial Statements, Captions [Line Items]
Total revenues	(582)	(652)	(1,178)	(1,421)
Expenses:
Direct operating	(1)	(1)	(2)	(1)
Depreciation of revenue earning equipment and lease charges, net	(581)	(651)	(1,176)	(1,420)
Selling, general and administrative	0	0	0	0
Interest expense, net	0	0	0	0
Other (income) expense, net	0	0	0	0
Total expenses	(582)	(652)	(1,178)	(1,421)
Income (loss) before income taxes	0	0	0	0
Provision for taxes on income	0	0	0	0
Equity in earnings (losses) of subsidiaries, net of tax	(244)	(277)	(490)	(502)
Net income (loss)	(244)	(277)	(490)	(502)
Other comprehensive income (loss), net of tax	(7)	(13)	43	6
Total comprehensive income (loss)	(251)	(290)	(447)	(496)
Parent
Condensed Financial Statements, Captions [Line Items]
Total revenues	1,181	1,212	2,296	2,334
Expenses:
Direct operating	720	739	1,414	1,420
Depreciation of revenue earning equipment and lease charges, net	452	538	907	1,201
Selling, general and administrative	155	132	267	266
Interest expense, net	86	88	176	172
Other (income) expense, net	(3)	(21)	(2)	(28)
Total expenses	1,410	1,476	2,762	3,031
Income (loss) before income taxes	(229)	(264)	(466)	(697)
Provision for taxes on income	76	94	44	254
Equity in earnings (losses) of subsidiaries, net of tax	176	243	376	449
Net income (loss)	23	73	(46)	6
Other comprehensive income (loss), net of tax	11	12	(35)	(6)
Total comprehensive income (loss)	34	85	(81)	0
Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Total revenues	702	700	1,359	1,356
Expenses:
Direct operating	384	384	762	742
Depreciation of revenue earning equipment and lease charges, net	203	174	387	343
Selling, general and administrative	58	49	120	98
Interest expense, net	6	5	11	11
Other (income) expense, net	(2)	(1)	(1)	(1)
Total expenses	649	611	1,279	1,193
Income (loss) before income taxes	53	89	80	163
Provision for taxes on income	(17)	(33)	(15)	(60)
Equity in earnings (losses) of subsidiaries, net of tax	68	34	114	53
Net income (loss)	104	90	179	156
Other comprehensive income (loss), net of tax	0	(1)	(4)	(3)
Total comprehensive income (loss)	104	89	175	153
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Total revenues	1,391	1,570	2,668	3,097
Expenses:
Direct operating	402	472	739	876
Depreciation of revenue earning equipment and lease charges, net	622	647	1,285	1,310
Selling, general and administrative	83	84	173	177
Interest expense, net	63	69	121	132
Other (income) expense, net	(5)	0	(1)	4
Total expenses	1,165	1,272	2,317	2,499
Income (loss) before income taxes	226	298	351	598
Provision for taxes on income	(86)	(111)	(40)	(252)
Equity in earnings (losses) of subsidiaries, net of tax	0	0	0	0
Net income (loss)	140	187	311	346
Other comprehensive income (loss), net of tax	7	14	(39)	(3)
Total comprehensive income (loss)	$ 147	$ 201	$ 272	$ 343