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Common Stock Repurchase Program - Additional Information (Detail) - USD ($) $ / shares in Units, shares in Millions | 1 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2017 | Feb. 28, 2017 | Nov. 30, 2016 | Jun. 30, 2017 | Jun. 30, 2016
Stock Repurchase Program [Line Items] |  |  |  |  |
Common stock repurchases |  |  |  | $ 250,000,000 |
Cash paid for repurchase of common stock |  |  |  | 250,000,000 | $ 500,000,000
Maximum capital allocated for repurchases of shares | $ 500,000,000 |  |  | $ 500,000,000 |
Accelerated Share Repurchase Agreement (ASR) [Member] |  |  |  |  |
Stock Repurchase Program [Line Items] |  |  |  |  |
Common stock repurchases | $ 250,000,000 |  | $ 225,000,000 |  |
Shares of common stock received under ASR | 2.7 | 0.4 | 2.8 |  |
Cash paid for repurchase of common stock | $ 250,000,000 |  | $ 225,000,000 |  |
Accelerated share repurchase, price per share | $ 73.46 |  | $ 63.41 | $ 73.46 |
Accelerated Share Repurchase Agreement (ASR) [Member] | Weighted Average [Member] |  |  |  |  |
Stock Repurchase Program [Line Items] |  |  |  |  |
Final weighted average per share purchase price during the repurchase period |  | $ 69.43 |  |  |

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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 Amount of stock repurchase plan authorized. + References No definition available. + 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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