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Acquisitions / Dispositions (Pro-Forma Information) (Details) - USD ($) $ / shares in Units, $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Business Combinations [Abstract] |  |  |
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual |  | $ 25 | $ 124
Revenue | $ 14,100 | 13,724 | 13,528
Income from continuing operations | 1,514 | 1,787 | 1,643
Net income attributable to the Company | $ 1,496 | $ 1,759 | $ 1,606
Basic net income per share: |  |  |
Basic net income per share - Continuing operations (in dollars per share) | $ 2.91 | $ 3.39 | $ 3.02
Basic net income per share - Net income attributable to the Company (in dollars per share) | 2.92 | 3.39 | 3.02
Diluted net income per share: |  |  |
Diluted net income per share - Continuing operations (in dollars per share) | 2.88 | 3.36 | 2.99
Diluted net income per share - Net income attributable to the Company (in dollars per share) | $ 2.88 | $ 3.36 | $ 2.99
Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual |  | $ 4 | $ 7
Business Combination, Acquisition Related Costs | $ 3 | $ 14 |

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- Definition The pro forma basic net income per share for a period as if the business combination or combinations had been completed at the beginning of a period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (h)(2)-(3) -URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463 + Details
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- Definition This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 25 -Paragraph 23 -URI http://asc.fasb.org/extlink&oid=84229725&loc=d3e1043-128460 + Details
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