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Revenues - Reserves for Discounts and Allowances (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] |  |  |
Beginning balance | $ 1,198.9 | $ 1,051.3 | $ 761.6
Current provisions relating to sales in current year | 4,102.5 | 3,698.6 | 3,389.1
Adjustments relating to prior years | (53.7) | (48.3) | (12.1)
Payments/returns relating to sales in current year | (3,061.2) | (2,778.6) | (2,440.4)
Payments/returns relating to sales in prior years | (910.5) | (724.1) | (646.9)
Ending balance | 1,276.0 | 1,198.9 | 1,051.3
Discounts |  |  |
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] |  |  |
Beginning balance | 131.1 | 127.8 | 109.6
Current provisions relating to sales in current year | 774.7 | 666.2 | 679.3
Adjustments relating to prior years | (1.0) | 0.3 | (0.3)
Payments/returns relating to sales in current year | (635.1) | (535.5) | (551.7)
Payments/returns relating to sales in prior years | (128.3) | (127.7) | (109.1)
Ending balance | 141.4 | 131.1 | 127.8
Contractual Adjustments |  |  |
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] |  |  |
Beginning balance | 1,027.3 | 888.8 | 606.0
Current provisions relating to sales in current year | 3,308.8 | 3,011.5 | 2,686.7
Adjustments relating to prior years | (54.0) | (54.1) | (10.0)
Payments/returns relating to sales in current year | (2,426.1) | (2,242.9) | (1,887.6)
Payments/returns relating to sales in prior years | (763.0) | (576.0) | (506.3)
Ending balance | 1,093.0 | 1,027.3 | 888.8
Returns |  |  |
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] |  |  |
Beginning balance | 40.5 | 34.7 | 46.0
Current provisions relating to sales in current year | 19.0 | 20.9 | 23.1
Adjustments relating to prior years | 1.3 | 5.5 | (1.8)
Payments/returns relating to sales in current year | 0.0 | (0.2) | (1.1)
Payments/returns relating to sales in prior years | (19.2) | (20.4) | (31.5)
Ending balance | $ 41.6 | $ 40.5 | $ 34.7

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