Per Share Data (Narrative) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended
	Jul. 10, 2018	Jun. 30, 2019	Jun. 30, 2018
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest		$ (114)	$ 173
Net Income (Loss) Attributable to Noncontrolling Interest		(3)	(3)
Net Income (Loss) Attributable to Parent		$ (111)	$ 176
Basic weighted average common shares outstanding		4,087	4,010
Diluted weighted average common shares outstanding		4,087	4,061
Basic net (loss) income per common share		$ (0.03)	$ 0.04
Diluted net (loss) income per common share		$ (0.03)	$ 0.04
Options and RSUs [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount			9
Options and Restricted Stock Units [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Number of shares that had no effect on computation of dilutive weighted average number of shares outstanding		0	47
Warrant [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Number of shares that had no effect on computation of dilutive weighted average number of shares outstanding		0	4
Class of Warrant or Right, Number of Securities Called by Warrants or Rights	55
Class of Warrant or Right, Exercise Price of Warrants or Rights	$ 5.25
Proceeds from Warrant Exercises	$ 287
Warrant [Member] | SoftBank [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Number of shares that had no effect on computation of dilutive weighted average number of shares outstanding			2
Employee Stock Option [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		90