CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	3 Months Ended		6 Months Ended	12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Jul. 10, 2013	Mar. 31, 2016	Mar. 31, 2015		Dec. 31, 2013
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Asset impairments				$ 166
Other changes in assets and liabilities:
Deferred purchase price from sale of receivables	$ 0	$ 0	$ 0		$ 0		$ 0
Cash flows from investing activities:
Proceeds from sale-leaseback transaction		0	0
Cash flows from financing activities:
Proceeds from sale of future lease receivables	0	0	0		0		0
Cash and cash equivalents, beginning of period				4,010
Cash and cash equivalents, end of period				2,641	4,010
Successor [Member]
Cash flows from operating activities:
Net loss	(151)	(9)		(1,995)	(3,345)		(1,860)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Asset impairments	0	0		0	2,133	[1]	0
Depreciation and amortization	1,297	0		7,088	5,349		2,934
Provision for losses on accounts receivable	153	0		455	892		261
Share-based and long-term incentive compensation expense	35	0		75	86		98
Deferred income tax (benefit) expense	46	(1)		123	(609)		32
Equity in losses of unconsolidated investments, net	0	0		0	0		0
Gain on previously-held equity interests	0	0		0	0		0
Amortization and accretion of long-term debt premiums and discounts	(74)	0		(316)	(303)		(160)
Loss on disposal of property, plant and equipment	75	0		487	0		0
Litigation	0	0		193	91		0
Other changes in assets and liabilities:
Accounts and notes receivable	(232)	(11)		(1,663)	(644)		(558)
Deferred purchase price from sale of receivables				2,478
Inventories and other current assets	173	0		(3,065)	(1,573)		(391)
Accounts payable and other current liabilities	(490)	8		(574)	481		25
Non-current assets and liabilities, net	(350)	0		111	(199)		(386)
Other, net	40	11		500	91		(56)
Net cash provided by (used in) operating activities	522	(2)		3,897	2,450		(61)
Cash flows from investing activities:
Capital expenditures - network and other	(1,488)	0		(4,680)	(5,422)		(3,847)
Capital expenditures - leased devices	0	0		(2,292)	(582)		0
Expenditures relating to FCC licenses	(152)	0		(98)	(163)		(146)
Reimbursements related to FCC licenses	0	0		0	95		0
Acquisitions, net of cash acquired	0	0		0	0		(14,112)
Investment in Clearwire (including debt securities)	0	0		0	0		0
Proceeds from sales and maturities of short-term investments	920	0		418	3,131		1,715
Purchases of short-term investments	(1,035)	0		(252)	(2,077)		(1,719)
Proceeds from sale of assets and FCC licenses	1	0		62	315		7
Proceeds from sale-leaseback transaction	0	0		1,136	0		0
Other, net	(2)	0		(29)	(11)		(6)
Net cash used in investing activities	(1,756)	0		(5,735)	(4,714)		(18,108)
Cash flows from financing activities:
Proceeds from debt and financings	0	0		755	1,930		9,500
Repayments of debt, financing and capital lease obligations	(159)	0		(899)	(574)		(3,378)
Proceeds from sale of future lease receivables				600
Debt financing costs	(1)	0		(11)	(87)		(147)
Proceeds from issuance of common stock and warrants, net	0	0		10	35		18,567
Other, net	0	0		14	0		(14)
Net cash provided by (used in) financing activities	(160)	0		469	1,304		24,528
Net (decrease) increase in cash and cash equivalents	(1,394)	(2)		(1,369)	(960)		6,359
Cash and cash equivalents, beginning of period	6,364	5	5	4,010	4,970		5
Cash and cash equivalents, end of period	$ 4,970	3		$ 2,641	$ 4,010		6,364
Predecessor [Member]
Cash flows from operating activities:
Net loss		(643)	(1,158)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Asset impairments		0	0
Depreciation and amortization		1,492	3,245
Provision for losses on accounts receivable		83	194
Share-based and long-term incentive compensation expense		17	37
Deferred income tax (benefit) expense		24	1,586
Equity in losses of unconsolidated investments, net		202	482
Gain on previously-held equity interests		0	(2,926)
Amortization and accretion of long-term debt premiums and discounts		14	9
Loss on disposal of property, plant and equipment		0	0
Litigation		0	0
Other changes in assets and liabilities:
Accounts and notes receivable		215	150
Inventories and other current assets		243	298
Accounts payable and other current liabilities		(734)	280
Non-current assets and liabilities, net		16	207
Other, net		11	267
Net cash provided by (used in) operating activities		940	2,671
Cash flows from investing activities:
Capital expenditures - network and other		(1,381)	(3,140)
Capital expenditures - leased devices		0	0
Expenditures relating to FCC licenses		(55)	(125)
Reimbursements related to FCC licenses		0	0
Acquisitions, net of cash acquired		0	(4,039)
Investment in Clearwire (including debt securities)		(80)	(308)
Proceeds from sales and maturities of short-term investments		1,281	2,445
Purchases of short-term investments		(926)	(1,221)
Proceeds from sale of assets and FCC licenses		6	10
Other, net		(3)	(7)
Net cash used in investing activities		(1,158)	(6,385)
Cash flows from financing activities:
Proceeds from debt and financings		204	204
Repayments of debt, financing and capital lease obligations		(59)	(362)
Debt financing costs		(10)	(11)
Proceeds from issuance of common stock and warrants, net		7	60
Other, net		0	0
Net cash provided by (used in) financing activities		142	(109)
Net (decrease) increase in cash and cash equivalents		(76)	(3,823)
Cash and cash equivalents, beginning of period		6,351	6,351				$ 6,351
Cash and cash equivalents, end of period		$ 6,275	$ 2,528

[1] (2)Impairments for the Successor year ended March 31, 2015 consist of a $1.9 billion trade name impairment related to the Wireless segment and a $233 million impairment related to Wireline long-lived assets.