CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2019	Mar. 31, 2018
Current assets:
Allowance for doubtful accounts	$ 60	$ 40
Accumulated amortization	3,399	2,603
Accumulated depreciation	$ 3,958	$ 3,686
CSC stockholders' equity:
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, authorized (in shares)	1,000,000	1,000,000
Preferred stock, shares issued (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized (in shares)	750,000,000	750,000,000
Common stock, issued (in shares)	270,213,891	286,393,147
Common stock in treasury, at cost (in shares)	1,788,658	1,016,947