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Adoption of New Accounting Standards and Reclassifications (Detail) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Change in Accounting Estimate [Line Items] |  |  |
Increase to net cash provided by operating activities | $ 3,180 | $ 3,006 | $ 2,528
Increase to net cash used in financing activities | $ (1,811) | (1,081) | (2,185)
Excess Tax Benefits Or Deficiencies [Member] | Accounting Standards Update 2016-09 [Member] |  |  |
Change in Accounting Estimate [Line Items] |  |  |
Increase to net cash provided by operating activities |  | 28 | 15
Increase to net cash used in financing activities |  | (28) | (15)
Tax Payments Associated with Equity Based Compensation Transactions [Member] | Accounting Standards Update 2016-09 [Member] |  |  |
Change in Accounting Estimate [Line Items] |  |  |
Increase to net cash provided by operating activities |  | 18 | 15
Increase to net cash used in financing activities |  | $ (18) | $ (15)

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- Definition Amount of cash inflow (outflow) from financing activities, including discontinued operations. Financing activity cash flows include obtaining resources from owners and providing them with a return on, and a return of, their investment; borrowing money and repaying amounts borrowed, or settling the obligation; and obtaining and paying for other resources obtained from creditors on long-term credit. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 24 -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3521-108585 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 26 -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3574-108585 + Details
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