Consolidated Balance Sheets (Parenthetical) (GBP £)	Dec. 31, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]
Common Stock, Par Value (in GBP per share)	£ 0.05	£ 0.05
Common Stock, Shares Authorized	1,000us-gaap_CommonStockSharesAuthorized	1,000us-gaap_CommonStockSharesAuthorized
Common Stock, Shares, Issued	599,100,000us-gaap_CommonStockSharesIssued	597,500,000us-gaap_CommonStockSharesIssued
Common Stock, Shares, Outstanding	599,100,000us-gaap_CommonStockSharesOutstanding	597,500,000us-gaap_CommonStockSharesOutstanding
Treasury Stock, Shares	10,600,000us-gaap_TreasuryStockShares	13,400,000us-gaap_TreasuryStockShares

Face amount or stated value per share of common stock.

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The maximum number of common shares permitted to be issued by an entity's charter and bylaws.

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Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

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Number of common and preferred shares that were previously issued and that were repurchased by the issuing entity and held in treasury on the financial statement date. This stock has no voting rights and receives no dividends.

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