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Capital Stock, Dividends and Common Stock Repurchase Program (ASR) (Detail) $ / shares in Units, shares in Thousands, $ in Millions | 1 Months Ended | 12 Months Ended |
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Feb. 28, 2017 $ / shares shares | Nov. 30, 2016 USD ($) shares | Dec. 31, 2017 USD ($) item $ / shares shares | Dec. 31, 2016 USD ($) item $ / shares shares | Dec. 31, 2015 USD ($) item $ / shares shares | Dec. 01, 2017 USD ($)
Accelerated Share Repurchases [Line Items] |  |  |  |  |  |
Shares repurchased | shares |  |  | 10,058 | 11,241 | 14,823 |
Weighted average per share purchase price | $ / shares |  |  | $ 77.67 | $ 60.49 | $ 49.83 |
Total repurchases |  |  | $ 750 | $ 725 | $ 600 |
Cash paid for repurchase of common stock |  |  | $ 750 | $ 725 | $ 600 |
Accelerated Share Repurchase Agreement (ASR) [Member] |  |  |  |  |  |
Accelerated Share Repurchases [Line Items] |  |  |  |  |  |
Shares repurchased | shares | 3,200 | 400 |  |  | 2,800 |
Weighted average per share purchase price | $ / shares | $ 69.43 |  |  |  |  |
Total repurchases |  | $ 225 |  |  |  |
Number of ASR agreements | item |  |  | 2 | 4 | 2 |
Cash paid for repurchase of common stock |  |  | $ 750 | $ 725 | $ 600 |
Authorized share repurchases |  |  |  |  |  | $ 1,250

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- Definition Final price paid per share for the purchase of the targeted number of shares, determined by an average market price over a fixed period of time. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 30 -Section 25 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6405686&loc=d3e22802-112653 + Details
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- Definition The cash outflow to reacquire common stock during the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 15 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3291-108585 + Details
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- Definition Number of shares that have been repurchased during the period and are being held in treasury. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=84159872&loc=d3e21463-112644 + Details
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- Definition Equity impact of the cost of common and preferred stock that were repurchased during the period. Recorded using the cost method. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=84159872&loc=d3e21463-112644 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 30 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6405813&loc=d3e23239-112655 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770 + Details
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