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Share Repurchases (Details) - USD ($) shares in Thousands, $ in Millions | 12 Months Ended |  |  |
--- | --- | --- | --- | ---
Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017 | Mar. 31, 2019 | Sep. 30, 2018 | Sep. 30, 2016
Class of Stock [Line Items] |  |  |  |  |  |
Preferred stock, shares authorized | 8,000 |  |  |  |  |
Payments for repurchase of common stock | $ 5,868.3 | $ 4,352.6 | $ 1,365.4 |  |  |
Series A |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |
Preferred stock, shares authorized | 1,750 |  |  |  |  |
Series X junior participating |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |
Preferred stock, shares authorized | 1,000 |  |  |  |  |
Undesignated |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |
Preferred stock, shares authorized | 5,250 |  |  |  |  |
December 2019 Share Repurchase Program [Member] |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |
Authorized amount of share repurchases | $ 5,000.0 |  |  |  |  |
March 2019 Share Repurchase Program |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |
Authorized amount of share repurchases |  |  |  | $ 5,000.0 |  |
Repurchase of common stock, at cost, shares | 14,700 |  |  |  |  |
Payments for repurchase of common stock | $ 3,700.0 |  |  |  |  |
2018 Share Repurchase Program |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |
Authorized amount of share repurchases |  |  |  |  | $ 3,500.0 |
Repurchase of common stock, at cost, shares | 8,900 | 4,300 |  |  |  |
Payments for repurchase of common stock | $ 2,100.0 | $ 1,400.0 |  |  |  |
2016 Share Repurchase Program |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |
Authorized amount of share repurchases |  |  |  |  |  | $ 5,000.0
Repurchase of common stock, at cost, shares |  | 10,500 | 3,700 |  |  |
Payments for repurchase of common stock |  | $ 3,000.0 | $ 1,000.0 |  |  |

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