v3.10.0.1

Equity (Details) - USD ($) | 6 Months Ended
--- | ---
Jun. 30, 2018 | Jun. 30, 2017
Class of Stock [Line Items] |  |
Total cost | $ 1,276,200,000 | $ 2,108,700,000
Remaining authorized repurchase amount | 783,900,000 |
Authorized amount | 500,000,000.0 |
Common Class A and Common Class C |  |
Class of Stock [Line Items] |  |
Total cost | $ 1,288,300,000 |
Class A |  |
Class of Stock [Line Items] |  |
Shares repurchased (in shares) | 12,588,800 |
Average price paid per share (in dollars per share) | $ 30.15 |
Class C |  |
Class of Stock [Line Items] |  |
Shares repurchased (in shares) | 29,342,800 |
Average price paid per share (in dollars per share) | $ 30.97 |

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