| In millions, except per share items | Dec-31-18 | Dec-31-17 | Dec-31-16 | Dec-31-15 | Dec-31-14 | Dec-31-13 | Dec-31-12 | Dec-31-11 |
| | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K |
| Net income | -698.0 | -107.6 | -91.2 | -83.4 | -37.8 | -21.5 | -29.3 | 19.9 |
| Depreciation and amortization [+] | 223.1 | 245.6 | 255.2 | 269.1 | 263.5 | 217.7 | 171.9 | 166.7 |
| Depreciation | 11.5 | 8.8 | 8.4 | 10.4 | 10.1 | 8.9 | 8.4 | 7.1 |
| Amortization of intangible assets | 211.6 | 236.8 | 246.8 | 258.7 | 253.4 | 208.8 | 163.5 | 159.6 |
| Asset impairment charges | 563.5 | | | | | | | |
| Stock-based compensation | 1.5 | 7.4 | 7.0 | 7.3 | 7.2 | 8.2 | 5.3 | 4.7 |
| Deferred taxes | -14.1 | -4.5 | 4.2 | 4.1 | -0.2 | 0.2 | 0.4 | 0.2 |
| Change in working capital [+] | 9.0 | 14.0 | 19.8 | 10.6 | -3.5 | 2.3 | 3.3 | -8.9 |
| Accounts receivable | -12.8 | -9.8 | -11.0 | -9.4 | -8.9 | -8.2 | -5.8 | -5.4 |
| Other current assets | -14.6 | -1.7 | 0.3 | -3.9 | 0.1 | 8.6 | -3.6 | 0.2 |
| Other | 36.3 | 25.5 | 30.5 | 23.8 | 5.4 | 1.8 | 12.7 | -3.8 |
| Other operating activities | 8.0 | -18.5 | -6.1 | 0.9 | 5.3 | | | |
| Cash from operations | 92.9 | 136.5 | 188.9 | 208.7 | 234.6 | 212.2 | 146.8 | 131.2 |
| |
| Capital expenditures [+] | -14.9 | -14.4 | -9.2 | -12.4 | -7.8 | -9.9 | -6.1 | -4.2 |
| Purchases of property and equipment | -14.9 | -14.4 | -9.2 | -12.4 | -7.8 | -9.9 | -6.1 | -4.2 |
| Sales of property and equipment | | 32.6 | | 20.2 | 0.2 | 12.9 | 17.3 | |
| Acquisitions | | | | -56.8 | | -478.7 | | |
| Purchases of short-term investments, net | 104.3 | -25.5 | 10.1 | 30.4 | 3.2 | 11.6 | -99.7 | -40.3 |
| Purchases of short-term investments | -39.0 | -26.6 | -5.0 | -26.9 | -4.6 | -21.8 | -99.7 | -40.3 |
| Sales of short-term investments | 143.3 | 1.1 | 15.2 | 57.3 | 7.8 | 33.4 | | |
| Other cash from investing | -140.5 | -142.9 | -201.4 | -266.6 | -268.6 | -232.4 | -248.7 | -61.7 |
| Cash from investing | -51.1 | -150.2 | -200.4 | -285.3 | -272.9 | -696.6 | -337.2 | -106.2 |
| |
| Repurchase of common stock, net | | | -7.1 | -30.0 | -35.7 | -33.4 | -12.9 | -11.5 |
| Option exercises | | | | | 0.8 | 0.2 | 0.3 | 1.3 |
| Financing costs | -10.7 | | -16.9 | -6.5 | | -11.1 | -46.7 | |
| Other cash from financing | 43.0 | 11.9 | 8.4 | 93.1 | 42.7 | 473.1 | 51.7 | 21.4 |
| Cash from financing | 53.8 | 11.9 | 18.2 | 69.6 | 6.2 | 450.6 | 85.2 | 8.7 |
| |
| Free cash flow | 78.0 | 122.1 | 179.7 | 196.2 | 226.8 | 202.3 | 140.7 | 127.0 |
| Per share (diluted) | $6.32 | $10.01 | $14.66 | $15.16 | $16.67 | $14.53 | $10.03 | $8.95 |
| |
| Cash paid for interest | 150.0 | 140.7 | 120.9 | 112.3 | 106.5 | 88.3 | 52.3 | 24.6 |
| Cash paid for income taxes | 2.5 | 2.7 | 2.6 | | | | | |