CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) INCOME - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Revenue, Net [Abstract]
Service	$ 5,967	$ 6,413	$ 12,038	$ 12,929
Equipment	1,960	1,834	4,046	3,330
Net operating revenues	7,927	8,247	16,084	16,259
Net operating expenses
Cost of Services (exclusive of depreciation and amortization included below)	1,698	2,101	3,407	4,200
Cost of Products (exclusive of depreciation and amortization included below)	1,404	1,693	2,949	3,112
Selling, general and administrative	2,013	1,995	3,951	3,912
Severance and exit costs	0	(5)	0	11
Depreciation	1,885	1,710	3,716	3,390
Amortization	209	271	432	558
Other, net	117	(140)	(135)	93
Total costs and expenses	7,326	7,625	14,320	15,276
Operating Income	601	622	1,764	983
Other (expense) income
Interest Expense	(595)	(630)	(1,208)	(1,245)
Other income, net	44	(15)	(8)	(7)
Nonoperating Expense	(551)	(645)	(1,216)	(1,252)
Loss (income) before income taxes	50	(23)	548	(269)
Income tax benefit	(98)	(119)	(390)	(175)
Net (loss) income	$ (48)	$ (142)	$ 158	$ (444)
Basic net (loss) income per common share	$ (0.01)	$ (0.04)	$ 0.04	$ (0.11)
Diluted net (loss) income per common share	$ (0.01)	$ (0.04)	$ 0.04	$ (0.11)
Basic weighted average common shares outstanding	3,998	3,979	3,996	3,977
Diluted weighted average common shares outstanding	3,998	3,979	4,080	3,977
Other comprehensive (loss) income, net of tax:
Net unrealized holding gains on securities and other	$ 13	$ 7	$ 18	$ 5
Net unrealized holding gains (losses) on derivatives	2	0	(7)	0
Net unrecognized net periodic pension and other postretirement benefits	1	1	1	2
Other comprehensive income	16	8	12	7
Comprehensive (loss) income	$ (32)	$ (134)	$ 170	$ (437)