Consolidated Statements of Comprehensive Income Consolidated Statement of Comprehensive Income (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Comprehensive Income [Abstract]
Net Income (Loss) Attributable to Parent	$ 1,774us-gaap_NetIncomeLoss	$ 1,344us-gaap_NetIncomeLoss	$ 1,958us-gaap_NetIncomeLoss
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	375	(597)	(1,343)
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	(182)	(253)	(37)
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	(26)	252	(60)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	167	(598)	(1,440)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	$ 1,941us-gaap_ComprehensiveIncomeNetOfTax	$ 746us-gaap_ComprehensiveIncomeNetOfTax	$ 518us-gaap_ComprehensiveIncomeNetOfTax

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Other Comprehensive Income

-URI http://asc.fasb.org/extlink&oid=6519514

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Comprehensive Income

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

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-Name Accounting Standards Codification

-Topic 220

-SubTopic 10

-Section 45

-Paragraph 5

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-Glossary Net Income

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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-Publisher SEC

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-Number 210

-Section 03

-Paragraph 19

-Article 5

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Amount after tax and reclassification adjustments, of appreciation (loss) in value of unsold available-for-sale securities. Excludes amounts related to other than temporary impairment (OTTI) loss.

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Amount after tax and reclassification adjustments, of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

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Amount after tax of other comprehensive income (loss) attributable to parent entity.

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Amount after tax and reclassification adjustments, of (increase) decrease in accumulated other comprehensive (income) loss related to pension and other postretirement defined benefit plans.

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