Guarantor Financial Information (CONDENSED CONSOLIDATED STATEMENT OF COMPREHENSIVE INCOME (LOSS)) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Condensed Income Statements, Captions [Line Items]
Net operating revenues	$ 7,975	$ 8,488	$ 16,002	$ 17,277
Cost of Services (exclusive of depreciation and amortization included below)	2,453	2,429	4,846	4,949
Cost of Products (exclusive of depreciation and amortization included below)	1,290	2,372	2,655	4,530
Net operating expenses
Selling, general and administrative	2,224	2,301	4,411	4,585
Impairments	85	0	85	0
Severance and exit costs	25	284	38	311
Depreciation	1,412	898	2,653	1,766
Amortization	331	396	678	809
Other, net	157	0	137	0
Total costs and expenses	7,977	8,680	15,503	16,950
Operating Income	(2)	(192)	499	327
Other (expense) income
Interest Income	1	4	4	7
Interest Expense	(542)	(510)	(1,084)	(1,022)
(Losses) earnings of Subsidiaries	0	0	0	0
Other income, net	4	4	5	2
Nonoperating Expense	(537)	(502)	(1,075)	(1,013)
Loss (income) before income taxes	(539)	(694)	(576)	(686)
Income tax benefit	(46)	(71)	(29)	(56)
Net (loss) income	(585)	(765)	(605)	(742)
Other Comprehensive Income (Loss), Net of Tax	(8)	(7)	(4)	(7)
Comprehensive (loss) income	(593)	(772)	(609)	(749)
Guarantor Subsidiaries [Member]
Condensed Income Statements, Captions [Line Items]
Net operating revenues	0	0	0	0
Cost of Services (exclusive of depreciation and amortization included below)	0	0	0	0
Cost of Products (exclusive of depreciation and amortization included below)	0	0	0	0
Net operating expenses
Selling, general and administrative	0	0	0	0
Impairments	0		0
Severance and exit costs	0	0	0	0
Depreciation	0	0	0	0
Amortization	0	0	0	0
Other, net	0		0
Total costs and expenses	0	0	0	0
Operating Income	0	0	0	0
Other (expense) income
Interest Income	40	23	79	46
Interest Expense	(407)	(364)	(814)	(732)
(Losses) earnings of Subsidiaries	(218)	(424)	130	(56)
Other income, net	0	0	0	0
Nonoperating Expense	(585)	(765)	(605)	(742)
Loss (income) before income taxes	(585)	(765)	(605)	(742)
Income tax benefit	0	0	0	0
Net (loss) income	(585)	(765)	(605)	(742)
Other Comprehensive Income (Loss), Net of Tax	(8)	(7)	(4)	(7)
Comprehensive (loss) income	(593)	(772)	(609)	(749)
Non-Guarantor Subsidiaries [Member]
Condensed Income Statements, Captions [Line Items]
Net operating revenues	7,975	8,488	16,002	17,277
Cost of Services (exclusive of depreciation and amortization included below)	2,453	2,429	4,846	4,949
Cost of Products (exclusive of depreciation and amortization included below)	1,290	2,372	2,655	4,530
Net operating expenses
Selling, general and administrative	2,224	2,301	4,411	4,585
Impairments	85		85
Severance and exit costs	25	284	38	311
Depreciation	1,412	898	2,653	1,766
Amortization	331	396	678	809
Other, net	157		137
Total costs and expenses	7,977	8,680	15,503	16,950
Operating Income	(2)	(192)	499	327
Other (expense) income
Interest Income	0	1	1	1
Interest Expense	(174)	(166)	(346)	(330)
(Losses) earnings of Subsidiaries	0	0	0	0
Other income, net	4	4	5	2
Nonoperating Expense	(170)	(161)	(340)	(327)
Loss (income) before income taxes	(172)	(353)	159	0
Income tax benefit	(46)	(71)	(29)	(56)
Net (loss) income	(218)	(424)	130	(56)
Other Comprehensive Income (Loss), Net of Tax	(6)	(1)	(2)	(1)
Comprehensive (loss) income	(224)	(425)	128	(57)
Consolidation, Eliminations [Member]
Condensed Income Statements, Captions [Line Items]
Net operating revenues	0	0	0	0
Cost of Services (exclusive of depreciation and amortization included below)	0	0	0	0
Cost of Products (exclusive of depreciation and amortization included below)	0	0	0	0
Net operating expenses
Selling, general and administrative	0	0	0	0
Impairments	0		0
Severance and exit costs	0	0	0	0
Depreciation	0	0	0	0
Amortization	0	0	0	0
Other, net	0		0
Total costs and expenses	0	0	0	0
Operating Income	0	0	0	0
Other (expense) income
Interest Income	(236)	(189)	(471)	(378)
Interest Expense	236	189	471	378
(Losses) earnings of Subsidiaries	803	1,189	475	798
Other income, net	0	0	0	0
Nonoperating Expense	803	1,189	475	798
Loss (income) before income taxes	803	1,189	475	798
Income tax benefit	0	0	0	0
Net (loss) income	803	1,189	475	798
Other Comprehensive Income (Loss), Net of Tax	14	8	6	8
Comprehensive (loss) income	817	1,197	481	806
Parent Company [Member]
Condensed Income Statements, Captions [Line Items]
Net operating revenues	0	0	0	0
Cost of Services (exclusive of depreciation and amortization included below)	0	0	0	0
Cost of Products (exclusive of depreciation and amortization included below)	0	0	0	0
Net operating expenses
Selling, general and administrative	0	0	0	0
Impairments	0		0
Severance and exit costs	0	0	0	0
Depreciation	0	0	0	0
Amortization	0	0	0	0
Other, net	0		0
Total costs and expenses	0	0	0	0
Operating Income	0	0	0	0
Other (expense) income
Interest Income	197	169	395	338
Interest Expense	(197)	(169)	(395)	(338)
(Losses) earnings of Subsidiaries	(585)	(765)	(605)	(742)
Other income, net	0	0	0	0
Nonoperating Expense	(585)	(765)	(605)	(742)
Loss (income) before income taxes	(585)	(765)	(605)	(742)
Income tax benefit	0	0	0	0
Net (loss) income	(585)	(765)	(605)	(742)
Other Comprehensive Income (Loss), Net of Tax	(8)	(7)	(4)	(7)
Comprehensive (loss) income	$ (593)	$ (772)	$ (609)	$ (749)