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Common Stock Repurchase Program (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions | 1 Months Ended | 3 Months Ended | 9 Months Ended
--- | --- | --- | ---
Mar. 31, 2020 | Feb. 29, 2020 | Mar. 31, 2020 | Sep. 30, 2020 | Sep. 30, 2019
Accelerated Share Repurchases [Line Items] |  |  |  |  |
Cash paid for repurchase of common stock |  |  |  | $ 402 | $ 248
Authorized share repurchases |  |  |  | $ 918 |
Accelerated Share Repurchase Agreement (ASR) [Member] |  |  |  |  |
Accelerated Share Repurchases [Line Items] |  |  |  |  |
Cash paid for repurchase of common stock |  | $ 313 |  |  |
Shares repurchased (in shares) | 0.8 | 2.0 |  |  |
Weighted average per share purchase price | $ 111.78 | $ 125.75 |  |  |
10b5-1 Plan [Member] |  |  |  |  |
Accelerated Share Repurchases [Line Items] |  |  |  |  |
Cash paid for repurchase of common stock |  |  | $ 89 |  |
Shares repurchased (in shares) |  |  | 0.9 |  |
Weighted average per share purchase price |  |  | $ 99.96 |  |

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- Definition The cash outflow to reacquire common stock during the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 15 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3291-108585 + Details
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