CONSOLIDATED BALANCE SHEET (Parenthetical) (USD $) In Millions, except Share data, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Receivables, allowances	$ 3	$ 3
Property and equipment, accumulated depreciation	$ 6,304	$ 6,324
Common shares, par value	$ 1.25	$ 1.25
Common shares, authorized	1,360,000,000us-gaap_CommonStockSharesAuthorized	1,360,000,000us-gaap_CommonStockSharesAuthorized
Common shares, issued	518,735,116us-gaap_CommonStockSharesIssued	524,474,315us-gaap_CommonStockSharesIssued
Common shares, outstanding	518,735,116us-gaap_CommonStockSharesOutstanding	524,474,315us-gaap_CommonStockSharesOutstanding
6.375 percent Mandatory Convertible Preference Shares, Series A
Preference shares, par value	$ 1.00	$ 1.00
Preference shares, liquidation	$ 50.00	$ 50.00
Preference shares, authorized	40,000,000	40,000,000
Preference shares, issued	13,800,000	13,800,000
Preference shares, outstanding	13,800,000	13,800,000

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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