Income Taxes (Contingencies) (Details) $ in Millions	9 Months Ended
Sep. 30, 2016 USD ($)
UTC \| Internal Revenue Service (IRS) [Member] \| Tax Year 2012 [Member]
Income Tax Contingency [Line Items]
Open Tax Year	2012
UTC \| Internal Revenue Service (IRS) [Member] \| Tax Year 2011 [Member]
Income Tax Contingency [Line Items]
Open Tax Year	2011
Minimum [Member] \| UTC \| Internal Revenue Service (IRS) [Member] \| Tax Year 2011 [Member]
Income Tax Contingency [Line Items]
Income Tax Examination, Liability (Refund) Adjustment from Settlement with Taxing Authority	$ (150)
Maximum [Member] \| UTC \| Internal Revenue Service (IRS) [Member] \| Tax Year 2012 [Member]
Income Tax Contingency [Line Items]
Income Tax Examination, Liability (Refund) Adjustment from Settlement with Taxing Authority	(275)
Settlement with Taxing Authority [Member]
Income Tax Contingency [Line Items]
Other Nonrecurring Gain	$ 58

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The amount of the additional liability or refund received or expected based on a final settlement with a taxing authority.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15A
-Subparagraph (3)
-URI http://asc.fasb.org/extlink&oid=65882285&loc=SL6600010-109319

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Tax year that remains open to examination under enacted tax laws, in CCYY format.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=65882285&loc=d3e32718-109319

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Amount of gain that is infrequent in occurrence or unusual in nature.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 20
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=64828382&loc=d3e15138-107781

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