Income Taxes (Net Deferred Tax Assets and Liabilities) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Components of Deferred Tax Assets and Liabilities [Abstract]
Deferred tax assets	$ 14,219us-gaap_DeferredTaxAssetsGross	$ 12,486us-gaap_DeferredTaxAssetsGross
Deferred tax liabilities	(16,028)us-gaap_DeferredIncomeTaxLiabilities	(15,664)us-gaap_DeferredIncomeTaxLiabilities
Valuation allowance	(81)	(125)
Net deferred tax (liabilities)/assets	$ (1,890)us-gaap_DeferredTaxAssetsNet	$ (3,303)us-gaap_DeferredTaxAssetsNet

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Amount of deferred tax liability attributable to taxable temporary differences.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Deferred Tax Liability

-URI http://asc.fasb.org/extlink&oid=6510232

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32537-109319

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 15

-Subparagraph b(2)

-Article 7

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- Definition

Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32537-109319

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Deferred Tax Asset

-URI http://asc.fasb.org/extlink&oid=6510090

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Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards.

+ References

+ Details

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- Definition

Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

+ References

+ Details

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