CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - 3 months ended Jun. 30, 2016 - USD ($) shares in Millions, $ in Millions	Total	Common Stock [Member]	Paid-in Capital [Member]	Treasury Stock [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Loss [Member]
Balance (in shares) at Mar. 31, 2016		3,974		1
Balance at Mar. 31, 2016	$ 19,783	$ 40	$ 27,563	$ (3)	$ (7,378)	$ (439)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(302)				(302)
Other Comprehensive Income (Loss), Net of Tax	(1)					(1)
Stock Issued During Period, Shares, New Issues		1
Stock Issued During Period, Value, New Issues	3		0
Stock Issued During Period, Shares, Treasury Stock Reissued				(1)
Stock Issued During Period, Value, Treasury Stock Reissued				$ 3
Share-based compensation expense	15		15
Capital Contribution By SoftBank	4		4
Balance (in shares) at Jun. 30, 2016		3,975		0
Balance at Jun. 30, 2016	$ 19,502	$ 40	$ 27,582	$ 0	$ (7,680)	$ (440)