Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2015	Mar. 31, 2014
Stockholders' Equity
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	100,000,000us-gaap_PreferredStockSharesAuthorized	100,000,000us-gaap_PreferredStockSharesAuthorized
Preferred stock, shares issued	0us-gaap_PreferredStockSharesIssued	0us-gaap_PreferredStockSharesIssued
Preferred stock, shares outstanding	0us-gaap_PreferredStockSharesOutstanding	0us-gaap_PreferredStockSharesOutstanding
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	800,000,000us-gaap_CommonStockSharesAuthorized	800,000,000us-gaap_CommonStockSharesAuthorized
Common stock, shares issued	384,000,000us-gaap_CommonStockSharesIssued	381,000,000us-gaap_CommonStockSharesIssued
Treasury stock, shares	152,000,000us-gaap_TreasuryStockShares	150,000,000us-gaap_TreasuryStockShares

Face amount or stated value per share of common stock.

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