Condensed Consolidated Balance Sheets (Parenthetical) (USD $) In Millions, except Share data, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Receivables, allowance for doubtful accounts	$ 111	$ 97
Preferred stock, par	$ 1	$ 1
Preferred stock, shares authorized	10,000,000us-gaap_PreferredStockSharesAuthorized	10,000,000us-gaap_PreferredStockSharesAuthorized
Preferred stock, issued	0us-gaap_PreferredStockSharesIssued	0us-gaap_PreferredStockSharesIssued
Common stock, par	$ 0.1667	$ 0.1667
Common stock, shares authorized	300,000,000us-gaap_CommonStockSharesAuthorized	300,000,000us-gaap_CommonStockSharesAuthorized
Common stock, shares issued	198,223,040us-gaap_CommonStockSharesIssued	197,951,551us-gaap_CommonStockSharesIssued
Treasury stock, shares	48,441,768us-gaap_TreasuryStockShares	48,347,541us-gaap_TreasuryStockShares

A valuation allowance for trade and other receivables due to an Entity within one year (or the normal operating cycle, whichever is longer) that are expected to be uncollectible.

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