| In millions, except per share items | Dec-31-21 | Dec-31-20 | Dec-31-19 | Dec-31-18 | Dec-31-17 | Dec-31-16 | Dec-31-15 | Dec-31-13 |
| | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K |
| Net income | 0.0 | -21.5 | -33.6 | 19.9 | 118.5 | 2.1 | 21.1 | 302.8 |
| Depreciation and amortization | 232.5 | 235.9 | 248.3 | 258.2 | 266.0 | 269.5 | 294.6 | |
| Depreciation | | | | | | | | 10.6 |
| Stock-based compensation | 18.6 | 19.2 | 22.9 | 19.6 | 15.9 | 11.3 | 7.3 | |
| Deferred taxes | | | | | | | -0.3 | |
| Change in working capital [+] | -37.8 | -7.0 | -28.7 | -33.4 | -79.5 | -86.6 | -118.2 | |
| Accounts receivable | 1.9 | 1.7 | 0.8 | -3.0 | -1.0 | -4.5 | -3.2 | |
| Other | -39.7 | -8.7 | -29.6 | -30.4 | -78.5 | -82.1 | -115.0 | |
| Other operating activities | 31.0 | 10.7 | 76.6 | -107.9 | -130.9 | -47.9 | -221.5 | |
| Cash from operations | 244.3 | 237.3 | 285.4 | 156.5 | 190.1 | 148.3 | -17.0 | |
| |
| Capital expenditures | -112.0 | -89.5 | -103.9 | -137.9 | -86.4 | -132.7 | -107.9 | |
| Purchases of property and equipment | -112.0 | -89.5 | -103.9 | -137.9 | -86.4 | -132.7 | -107.9 | |
| Acquisitions | | | | -10.0 | | | | |
| Sales of short-term investments, net [+] | 18.7 | 6.4 | 4.1 | 4.8 | -2.0 | -0.4 | -1.5 | |
| Purchases of short-term investments | -21.6 | -15.8 | -15.2 | -20.0 | -29.2 | -2.7 | -8.6 | |
| Sales of short-term investments | 40.2 | 22.2 | 19.3 | 24.8 | 27.3 | 2.4 | 7.1 | |
| Other cash from investing | -10.1 | 123.1 | -223.6 | 299.8 | 384.2 | -519.6 | | |
| Cash from investing | -103.5 | 40.0 | -323.4 | 156.6 | 295.7 | -652.7 | -109.3 | |
| |
| Cash dividends paid | -61.3 | -89.2 | -93.0 | -95.0 | -89.3 | -82.1 | -85.5 | |
| Repurchase of common stock, net | | -120.0 | -97.1 | -102.9 | | | | |
| Financing costs | -16.8 | | -10.1 | | | | -18.9 | |
| Other cash from financing | -32.0 | 65.8 | 184.1 | -0.3 | -338.5 | 601.1 | -115.7 | |
| Cash from financing | -76.5 | -143.5 | 4.1 | -198.1 | -427.8 | 519.0 | -182.3 | |
| |
| Free cash flow | 132.3 | 147.8 | 181.5 | 18.6 | 103.7 | 15.6 | -124.8 | |
| Per share (diluted) | $0.60 | $0.66 | $0.78 | $0.03 | $0.15 | $0.07 | ($0.59) | |
| |
| Cash paid for interest | 132.5 | 135.6 | 139.1 | 136.5 | 132.4 | 140.1 | 159.2 | |
| Cash paid for income taxes | 1.8 | 1.4 | 2.5 | 4.0 | 5.0 | 2.1 | 2.8 | |