Investments (Additional Information) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2014	Mar. 31, 2013
Variable Interest Entity [Line Items]
Income from continuing operations, net of tax	$ 277	$ 191

Amount of income (loss) from continuing operations attributable to the parent. Also defined as revenue less expenses and taxes from ongoing operations before extraordinary items but after deduction of those portions of income or loss from continuing operations that are allocable to noncontrolling interests.

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

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

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Reference 4: http://www.xbrl.org/2003/role/presentationRef

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Reference 6: http://www.xbrl.org/2003/role/presentationRef

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+ Details