Capital Stock (Details Textual) (USD $) In Millions, except Share data, unless otherwise specified	1 Months Ended	3 Months Ended
Apr. 30, 2012	Mar. 31, 2012	Mar. 31, 2011
Capital Stock (Textual) [Abstract]
Options and restricted stock, anti-dilutive		2,900,000	1,600,000
Public offering of common stock underwritten	6,272,667
Common stock dividend paid		$ 58	$ 57
Dividend paid, Series D preferred stock		$ 19	$ 19
Performance Period		3 years
Percentage of restricted stock units awarded immediately vest		50.00%
Percentage of additional vest on succeeding anniversaries		25.00%
Performance Program 2012 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Initial conditional restricted stock unit awards granted to eligible employees		851,985
Nonvested shares outstanding		840,525
Minimum units awarded based upon measurement		0
Maximum units awarded based upon measurement		2,101,313

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

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Equity impact of preferred stock cash dividends declared by an entity during the period. This element includes paid and unpaid dividends declared during the period.

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