Summary of Significant Accounting Policies (Details 2) (USD $) In Millions, except Share data	3 Months Ended	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Basic earnings (loss) per share - continuing operations:
Income from continuing operations attributable to common shareholders, net of tax	$ 177	$ 343	$ 379	$ 572
Participating securities dividends		(2)		(2)
Income from continuing operations available to common shareholders	177	341	379	570
Weighted average common shares outstanding (in shares)	326,000,000	326,000,000	326,000,000	326,000,000
Basic earnings per share - continuing operations (in dollars per share)	$ 0.54	$ 1.05	$ 1.16	$ 1.75
Diluted earnings (loss) per share - continuing operations:
Income from continuing operations available to common shareholders	177	341	379	570
Income impact of assumed conversions	1	1	1	1
Income from continuing operations available to common shareholders and assumed conversions	$ 178	$ 342	$ 380	$ 571
Weighted-average shares of common stock outstanding (in shares)	326,000,000	326,000,000	326,000,000	326,000,000
Incremental shares from assumed conversions (in shares)	3,000,000	1,000,000	2,000,000	1,000,000
Adjusted weighted average shares - diluted (in shares)	329,000,000	327,000,000	328,000,000	327,000,000
Diluted earnings (loss) per share - continuing operations (in dollars per share)	$ 0.54	$ 1.05	$ 1.16	$ 1.75
Stock-based compensation awards
Antidilutive Securities Excluded from Computation of Earnings Per Share
Stock-based compensation awards excluded from the computation of diluted earnings per share (in shares)	5,896,940	9,645,334	5,896,940	6,080,199

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Participating securities shall be assumed to have been converted at the beginning of the period (or at the time of issuance, if later), and the resulting common shares shall be included in common shares used to calculate diluted earnings per share.

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This element includes the amount of dividends declared or paid in the period to participating shareholders or the amount for which the obligation to pay dividends arose in the period. Participating securities are stock based compensation awards payable in common shares, including stock options, performance shares and restricted stock units, which earn dividend equivalents on an equal basis with common shares.

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Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) in the future that were not included in the computation of diluted EPS because to do so would increase EPS amounts or decrease loss per share amounts for the period presented.

+ References

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Includes adjustments resulting from the assumption that dilutive convertible securities were converted, options or warrants were exercised, or that other shares were issued upon the satisfaction of certain conditions.

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This element represents the income or loss from continuing operations attributable to the reporting entity which may also be defined as revenue less expenses and taxes from ongoing operations before extraordinary items and cumulative effects of changes in accounting principles, but after deduction of those portions of income or loss from continuing operations that are allocable to noncontrolling interests, if any.

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The amount of income (loss) from continuing operations per each share of common stock outstanding during the reporting period.

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The amount of income (loss) from continuing operations available to each share of common stock outstanding during the reporting period and each share that would have been outstanding assuming the issuance of common shares for all dilutive potential common shares outstanding during the reporting period.

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Net income after adjustments for dividends on preferred stock (declared in the period) and/or cumulative preferred stock (accumulated for the period).

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Net Income (Loss) Available to Common Stockholders plus adjustments resulting from the assumption that dilutive convertible securities were converted, options or warrants were exercised, or that other shares were issued upon the satisfaction of certain conditions.

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The average number of shares issued and outstanding that are used in calculating diluted EPS, determined based on the timing of issuance of shares in the period.

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Number of [basic] shares, after adjustment for contingently issuable shares and other shares not deemed outstanding, determined by relating the portion of time within a reporting period that common shares have been outstanding to the total time in that period.

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