| In millions, except per share items | Dec-31-22 | Dec-31-21 | Dec-31-20 | Dec-31-19 | Dec-31-18 | Dec-31-17 | Dec-31-16 | Dec-31-15 |
| | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K |
| Property revenues | | | | | | | | |
| Property revenues | 1,422.8 | 1,143.6 | 1,043.8 | 1,028.5 | 954.5 | | | |
| |
| Property expenses | | | | | | | | |
| Property operating and maintenance | 315.7 | 267.7 | 252.2 | 235.6 | 220.7 | 217.8 | 206.8 | 202.1 |
| Real estate taxes | 182.3 | 149.3 | 142.6 | 130.8 | 122.8 | 110.9 | 104.6 | 98.9 |
| Total property expenses | 2,424.5 | 1,963.0 | 1,787.2 | 1,670.4 | 1,523.9 | 1,445.4 | 1,034.1 | 1,000.2 |
| |
| Non-property income/(loss) | | | | | | | | |
| Fee and asset management | 5.2 | 10.5 | 10.8 | 8.7 | 7.2 | 8.2 | 750.6 | 835.6 |
| Fee and asset management growth | -50.7% | -2.5% | 24.2% | 20.3% | -11.6% | -98.9% | -10.2% | 5.7% |
| Interest and other income | 3.0 | 1.2 | 2.9 | 3.1 | 2.1 | 3.0 | 2.2 | 0.6 |
| Income/(loss) on deferred compensation plans | -19.6 | 14.4 | 12.0 | | | | | |
| Total non-property income/(loss) | -11.4 | 26.1 | 25.8 | | | | | |
| |
| Other expenses | | | | | | | | |
| Property management | 28.6 | 26.3 | 24.2 | 25.3 | 25.6 | 25.8 | | |
| Fee and asset management | 2.5 | 4.5 | 4.0 | 5.8 | 4.5 | | | |
| General and administrative | 60.4 | 59.4 | 53.6 | 53.2 | 50.7 | 50.6 | 47.4 | 46.2 |
| Interest | -113.4 | -97.3 | -91.5 | -80.7 | -84.3 | -86.8 | -93.1 | -97.3 |
| Depreciation and amortization | 577.0 | 420.7 | 367.2 | 336.3 | 300.9 | 264.0 | 250.1 | 240.9 |
| Expense/(benefit) on deferred compensation plans | -19.6 | 14.4 | 12.0 | | | | | |
| Total other expenses | 2,424.5 | 1,963.0 | 1,787.2 | 1,670.4 | 1,523.9 | 1,445.4 | 1,034.1 | 1,000.2 |
| Gain (Loss) on Extinguishment of Debt | | | -0.2 | -12.0 | | -0.3 | | |
| Gain on sale of operating property | 36.4 | 174.4 | 0.4 | 49.9 | | 43.2 | 295.4 | 104.3 |
| |
| Equity in income of joint ventures | | | | | | | | |
| Income from continuing operations before income taxes | 664.5 | 314.3 | 130.6 | 225.4 | 162.1 | 202.1 | 457.0 | 240.4 |
| Income tax expense | -3.0 | -1.9 | -2.0 | -1.1 | -1.4 | -1.2 | -1.6 | -1.9 |
| Net Income (Loss), Including Portion Attributable to Noncontrolling Interest, Total | 661.5 | 312.4 | 128.6 | 224.3 | 160.7 | 200.9 | 838.2 | 258.3 |
| Less income allocated to non-controlling interests | -7.9 | -8.5 | -4.7 | -4.6 | -4.6 | -4.4 | -18.4 | -8.9 |
| Net income attributable to common shareholders | 653.6 | 303.9 | 123.9 | 219.6 | 156.1 | 196.4 | 819.8 | 249.3 |
| |
| Earnings per share – basic | $6.07 | $2.97 | $1.24 | $2.23 | $1.63 | $2.14 | $9.08 | $2.77 |
| Earnings per share – diluted | $6.04 | $2.96 | $1.24 | $2.22 | $1.63 | $2.13 | $9.05 | $2.76 |
| |
| Weighted average number of common shares outstanding – basic | 107.6 | 102.0 | 99.4 | 98.5 | 95.2 | 91.5 | 89.6 | 89.1 |
| Weighted average number of common shares outstanding – diluted | 108.4 | 102.8 | 99.4 | 99.4 | 95.4 | 92.5 | 89.9 | 89.5 |
| |
| Condensed Consolidated Statements of Comprehensive Income | | | | | | | | |
| Net income | 661.5 | 312.4 | 128.6 | 224.3 | 160.7 | 200.9 | 838.2 | 258.3 |
| |
| Other comprehensive income | | | | | | | | |
| |
| Comprehensive income | | | | | | | | |
| Less income allocated to non-controlling interests | 7.9 | 8.5 | 4.7 | 4.6 | 4.6 | 4.4 | 18.4 | 8.9 |
| Comprehensive income attributable to common shareholders | 655.6 | 305.6 | 125.1 | 206.2 | 163.1 | 198.2 | 819.9 | 249.8 |