CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) INCOME - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015
Revenue, Net [Abstract]
Service	$ 6,323	$ 6,683	$ 19,252	$ 20,600
Equipment	2,226	1,424	5,556	3,509
Net operating revenues	8,549	8,107	24,808	24,109
Net operating expenses
Cost of Services (exclusive of depreciation and amortization included below)	1,925	2,348	6,125	7,194
Cost of Products (exclusive of depreciation and amortization included below)	1,985	1,589	5,097	4,244
Selling, general and administrative	2,080	2,129	5,992	6,540
Severance and exit costs	19	209	30	247
Depreciation	1,837	1,549	5,227	4,202
Amortization	255	316	813	994
Other, net	137	164	230	386
Total costs and expenses	8,238	8,304	23,514	23,807
Operating Income	311	(197)	1,294	302
Other (expense) income
Interest Expense	(619)	(546)	(1,864)	(1,630)
Other income, net	(60)	4	(67)	13
Nonoperating Expense	(679)	(542)	(1,931)	(1,617)
Loss (income) before income taxes	(368)	(739)	(637)	(1,315)
Income tax benefit	(111)	(97)	(286)	(126)
Net (loss) income	$ (479)	$ (836)	$ (923)	$ (1,441)
Basic net (loss) income per common share	$ (0.12)	$ (0.21)	$ (0.23)	$ (0.36)
Diluted net (loss) income per common share	$ (0.12)	$ (0.21)	$ (0.23)	$ (0.36)
Basic weighted average common shares outstanding	3,983	3,970	3,979	3,969
Diluted weighted average common shares outstanding	3,983	3,970	3,979	3,969
Other comprehensive (loss) income, net of tax:
Net unrealized holding gains on securities and other	$ (5)	$ (9)	$ 0	$ (16)
Net unrecognized net periodic pension and other postretirement benefits	0	2	2	5
Other comprehensive income	(5)	(7)	2	(11)
Comprehensive (loss) income	$ (484)	$ (843)	$ (921)	$ (1,452)