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Capital Stock, Dividends and Common Stock Repurchase Program (Detail) $ / shares in Units, shares in Thousands, $ in Millions | 2 Months Ended | 12 Months Ended
--- | --- | ---
Feb. 14, 2019 USD ($) | Dec. 31, 2020 USD ($) $ / shares shares | Dec. 31, 2019 USD ($) $ / shares shares | Dec. 31, 2018 USD ($) item $ / shares shares
Accelerated Share Repurchases [Line Items] |  |  |  |
Cash paid for repurchase of common stock |  | $ 402 | $ 248 | $ 1,004
Shares repurchased (in shares) | shares |  | 3,687 | 2,247 | 11,673
Weighted average per share purchase price | $ / shares |  | $ 108.92 | $ 108.60 | $ 86.35
Total repurchases |  | $ 402 | $ 244 | $ 1,008
Authorized share repurchases |  | 1,350 |  |
Accelerated Share Repurchase Agreement (ASR) [Member] |  |  |  |
Accelerated Share Repurchases [Line Items] |  |  |  |
Cash paid for repurchase of common stock |  | $ 313 | $ 180 | $ 850
Shares repurchased (in shares) | shares |  | 2,800 | 1,600 | 9,800
Number of ASR agreements | item |  |  |  | 4
10b5-1 Plan [Member] |  |  |  |
Accelerated Share Repurchases [Line Items] |  |  |  |
Cash paid for repurchase of common stock | $ 4 | $ 89 | $ 64 | $ 158
Shares repurchased (in shares) | shares |  | 900 | 700 | 1,900

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