CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $) In Millions, except Share data, unless otherwise specified		Predecessor [Member] USD ($)	Predecessor [Member] Common Stock [Member] USD ($)	Predecessor [Member] Paid-in Capital [Member] USD ($)	Predecessor [Member] Treasury Shares [Member] USD ($)	Predecessor [Member] Accumulated Deficit [Member] USD ($)	Predecessor [Member] Accumulated Other Comprehensive (Loss) Income [Member] USD ($)	Successor [Member] USD ($)		Successor [Member] Common Stock [Member] USD ($)		Successor [Member] Paid-in Capital [Member] USD ($)		Successor [Member] Treasury Shares [Member] USD ($)		Successor [Member] Accumulated Deficit [Member] USD ($)		Successor [Member] Accumulated Other Comprehensive (Loss) Income [Member] USD ($)		SoftBank [Member] Successor [Member] USD ($)	SoftBank [Member] Successor [Member] Common Stock [Member] USD ($)	SoftBank [Member] Successor [Member] Paid-in Capital [Member] USD ($)	Common Class B [Member] Successor [Member] Common Stock [Member]
Balance at Dec. 31, 2011		$ 11,427	$ 5,992	$ 46,716	$ 0	$ (40,489)	$ (792)
Balance (in shares) at Dec. 31, 2011			2,996,000,000		0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income		(4,326)				(4,326)
Other comprehensive (loss) income		(341)					(341)
Issuance of common stock, net (in shares)			14,000,000
Issuance of common stock, net		29	27	2
Share-based compensation expense		44		44
Beneficial conversion feature on convertible bond		254		254
Common stock, shares, issued																							3,000,000
Balance at Dec. 31, 2012		7,087	6,019	47,016	0	(44,815)	(1,133)							0	[1]
Balance (in shares) at Dec. 31, 2012			3,010,000,000		0									0	[1]
Balance at Oct. 05, 2012	[1]							0		0		0		0		0		0
Balance (in shares) at Oct. 05, 2012	[1]									0				0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income								(27)								(27)
Other comprehensive (loss) income								0
Capital contribution by SoftBank												3,105
Expenses incurred by SoftBank for the benefit of Sprint								32				32
Common stock, shares, issued																							3,000,000
Balance at Dec. 31, 2012		7,087			0			3,110	[1]			3,137	[1]	0	[1]	(27)	[1]
Balance (in shares) at Dec. 31, 2012					0									0	[1]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income		(643)						(9)
Other comprehensive (loss) income		14						0
Balance at Mar. 31, 2013
Balance at Dec. 31, 2012		7,087	6,019	47,016	0	(44,815)	(1,133)							0	[1]
Balance (in shares) at Dec. 31, 2012			3,010,000,000		0									0	[1]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income		(1,158)				(1,158)
Other comprehensive (loss) income		23					23
Issuance of common stock, net (in shares)			16,000,000
Issuance of common stock, net		60	33	27
Share-based compensation expense		18		18
Conversion of convertible debt (in shares)			590,000,000
Conversion of convertible debt			1,181
Adjustments to paid in capital, conversation of convertible debt				1,919
Beneficial conversion feature on convertible bond		3,100
Balance at Jul. 10, 2013		9,130	7,233	48,980	0	(45,973)	(1,110)
Balance (in shares) at Jul. 10, 2013			3,616,000,000		0
Balance at Dec. 31, 2012					0			3,110	[1]	0	[1]	3,137	[1]	0	[1]	(27)	[1]	0	[1]
Balance (in shares) at Dec. 31, 2012					0					0	[1]			0	[1]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income								(1,860)								(1,860)
Other comprehensive (loss) income								102										102
Issuance of common stock, net (in shares)										7,000,000
Issuance of common stock, net								27				27
Share-based compensation expense								45				45
Expenses incurred by SoftBank for the benefit of Sprint								97				97
Issuance of common stock to stockholders upon acquisition (in shares)										851,000,000											3,076,000,000
Issuance of common stock to stockholders upon acquisition								5,344		8		5,336								18,401	31	18,370
Conversion of Sprint vested stock-based awards upon acquisition								193				193
Issuance of warrant to SoftBank prior to acquisition								139				139
Return of capital to SoftBank prior to acquisition								(14)				(14)
Balance at Dec. 31, 2013								25,584		39		27,330		0		(1,887)		102
Balance (in shares) at Dec. 31, 2013										3,934,000,000				0
Balance at Jun. 30, 2013
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income		1,082
Balance at Jul. 10, 2013		9,130			0
Balance (in shares) at Jul. 10, 2013					0
Balance at Sep. 30, 2013
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income								(1,038)
Balance at Dec. 31, 2013								25,584		39		27,330		0		(1,887)		102
Balance (in shares) at Dec. 31, 2013										3,934,000,000				0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income								(151)								(151)
Other comprehensive (loss) income								(145)										(145)
Issuance of common stock, net (in shares)										7,000,000
Issuance of common stock, net								0
Share-based compensation expense								24				24
Common stock, shares, issued								3,941,000,000
Balance at Mar. 31, 2014								25,312		39		27,354				(2,038)		(43)
Balance (in shares) at Mar. 31, 2014										3,941,000,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income								23
Balance at Jun. 30, 2014
Balance at Mar. 31, 2014								25,312		39		27,354		0		(2,038)		(43)
Balance (in shares) at Mar. 31, 2014										3,941,000,000				0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income								(3,345)								(3,345)
Other comprehensive (loss) income								(365)										(365)
Issuance of common stock, net (in shares)										26,000,000
Issuance of common stock, net								35		1		41
Issuance (repurchase) of common stock, net (in shares)														1,000,000
Issuance (repurchase) of common stock, net														(7)
Share-based compensation expense								71				71
Capital contribution by SoftBank												2
Common stock, shares, issued								3,967,000,000
Balance at Mar. 31, 2015								21,710		40		27,468		(7)		(5,383)		(408)
Balance (in shares) at Mar. 31, 2015										3,967,000,000				1,000,000
Balance at Dec. 31, 2014
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income								(224)
Common stock, shares, issued								3,967,000,000
Balance at Mar. 31, 2015								$ 21,710

[1] (1)For the Successor period beginning October 5, 2012 and ending December 31, 2012, there were approximately 3 million shares of Class B common stock of Starburst II, Inc. issued and outstanding with an immaterial value. These shares were exchanged in connection with the issuance of common stock to SoftBank upon completion of the Merger.