| In millions, except per share items | Sep-30-22 | Sep-30-21 | Sep-30-20 | Sep-30-19 | Sep-30-18 | Sep-30-17 | Sep-30-16 | Sep-30-15 |
| | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K |
| Net income | 373.5 | 392.1 | 236.4 | 192.1 | 126.5 | 133.4 | 109.4 | 86.5 |
| Depreciation and amortization [+] | 20.5 | 25.6 | 30.4 | 31.6 | 30.2 | 36.2 | 31.6 | 33.9 |
| Depreciation | 18.4 | 22.3 | 25.4 | 25.5 | 23.6 | 23.5 | 17.7 | 20.2 |
| Amortization | 2.1 | 3.3 | 5.0 | 6.1 | 6.6 | 12.7 | 14.0 | 13.7 |
| Stock-based compensation | 115.4 | 112.5 | 93.7 | 83.0 | 74.8 | 61.2 | 55.5 | 45.3 |
| Tax benefit from stock-based compensation | | | | | | | 24.2 | 12.5 |
| Deferred taxes | 7.8 | -6.0 | -8.6 | 7.7 | 10.6 | -6.2 | -26.0 | -5.9 |
| Change in working capital [+] | -47.7 | -8.9 | -36.0 | -55.8 | -6.5 | -0.6 | 13.5 | -27.7 |
| Accounts receivable | -31.6 | 24.5 | -59.9 | -36.2 | -8.3 | 2.9 | -18.2 | -4.6 |
| Other current assets | 7.4 | -5.7 | -1.0 | -55.5 | -9.8 | -9.9 | 12.8 | -15.5 |
| Accounts payable | -2.8 | -2.4 | 1.1 | 1.9 | 0.8 | -2.0 | 0.6 | -3.7 |
| Deferred revenues | 23.5 | 4.5 | 5.7 | 10.5 | -4.8 | 2.0 | 5.5 | -6.6 |
| Other | -44.2 | -29.8 | 18.1 | 23.5 | 15.5 | 6.4 | 12.8 | 2.6 |
| Other operating activities | 40.0 | -91.5 | 49.1 | 1.7 | -12.5 | 1.7 | 2.0 | 2.2 |
| Cash from operations | 509.5 | 423.8 | 364.9 | 260.4 | 223.1 | 225.6 | 210.3 | 146.8 |
| |
| Capital expenditures [+] | -6.0 | -7.6 | -22.0 | -24.0 | -31.3 | -19.8 | -22.0 | -25.0 |
| Purchases of property and equipment | -6.0 | -7.6 | -22.0 | -24.0 | -31.3 | -19.8 | -22.0 | -25.0 |
| Sales of property and equipment | 2.3 | 147.4 | | | | | | |
| Acquisitions | | | | -15.9 | | | -5.7 | -57.0 |
| Purchases of short-term investments, net | -1.9 | -1.8 | -2.6 | -2.9 | -2.8 | | | |
| Purchases of short-term investments | -10.0 | -9.0 | -6.1 | -6.4 | -6.1 | | | |
| Sales of short-term investments | 8.1 | 7.2 | 3.5 | 3.5 | 3.2 | | | |
| Other cash from investing | | -0.2 | 0.1 | | 20.0 | -0.8 | 0.0 | 0.1 |
| Cash from investing | -5.7 | 137.9 | -24.6 | -42.8 | -14.1 | -20.6 | -27.6 | -81.9 |
| |
| Cash dividends paid | | | | | | -1.2 | -2.5 | -2.5 |
| Repurchase of common stock, net | -1,104.2 | -874.2 | -235.2 | -228.9 | -342.6 | -187.6 | -138.4 | -130.7 |
| Option exercises | 16.0 | 20.9 | 42.3 | 22.8 | 11.0 | 14.5 | 17.8 | 18.3 |
| Financing costs | -8.8 | -1.5 | -6.8 | | -7.8 | | | |
| Other cash from financing | 564.2 | 370.0 | -18.8 | 51.6 | 127.1 | 22.7 | -31.3 | 79.1 |
| Cash from financing | -547.2 | -523.6 | -289.4 | -200.0 | -218.6 | -180.6 | -190.0 | -72.4 |
| |
| Free cash flow | 503.4 | 416.2 | 342.9 | 236.4 | 191.8 | 205.8 | 188.3 | 121.8 |
| Per share (diluted) | $19.11 | $14.23 | $11.46 | $7.80 | $6.15 | $6.38 | $5.83 | $3.73 |
| |
| Cash paid for interest | 57.2 | 38.0 | 37.7 | 39.9 | 26.1 | 26.1 | 26.9 | 30.5 |
| Cash paid for income taxes | 65.3 | 71.5 | 10.2 | 18.8 | 13.4 | 31.3 | 22.2 | 33.8 |