CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2020	Mar. 31, 2019
Current assets:
Allowance for doubtful accounts	$ 74	$ 60
Accumulated amortization	4,347	3,399
Less: accumulated depreciation	$ 3,818
Accumulated depreciation		$ 3,958
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)	255,674,040	270,213,891
Common stock in treasury, at cost (in shares)	2,148,708	1,788,658