Equity (Details) - USD ($)	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Class of Stock [Line Items]
Issuance of common stock, net					$ 206,193,000	$ 833,000
Changes in equity
Beginning Balance	$ 10,733,999,000	$ 10,632,606,000	$ 10,335,124,000	$ 10,388,046,000	10,632,606,000	10,388,046,000
Net income attributable to common stockholders	168,281,000	170,366,000	254,662,000	141,643,000	338,647,000	396,305,000
(Loss) gain on cash flow hedges	(2,888,000)	(7,231,000)	0	11,501,000	(10,119,000)	11,499,000
Cash flow hedge losses reclassified to earnings	1,611,000	1,468,000	1,455,000	1,756,000	3,079,000	3,213,000
Change in redemption value of redeemable noncontrolling interest	(45,000)	(224,000)	(291,000)	(63,000)
Noncontrolling interest contribution	530,000
Dividends declared to common stockholders ($1.52 per share)	(212,549,000)	(212,166,000)	(203,472,000)	(203,166,000)
Issuance of common stock, net of withholdings	50,806,000	141,319,000	628,000	(11,142,000)
Amortization of deferred compensation	10,785,000	7,861,000	10,082,000	6,549,000
Ending Balance	$ 10,750,530,000	$ 10,733,999,000	$ 10,398,188,000	$ 10,335,124,000	10,750,530,000	10,398,188,000
Dividends declared to common stockholders (in dollars per share)	$ 1.52	$ 1.52	$ 1.47	$ 1.47
Common stock
Changes in equity
Beginning Balance	$ 1,394,000	$ 1,385,000	$ 1,382,000	$ 1,381,000	1,385,000	1,381,000
Issuance of common stock, net of withholdings	3,000	9,000	0	1,000
Ending Balance	1,397,000	1,394,000	1,382,000	1,382,000	1,397,000	1,382,000
Additional paid-in capital
Changes in equity
Beginning Balance	10,457,651,000	10,306,588,000	10,229,738,000	10,235,475,000	10,306,588,000	10,235,475,000
Issuance of common stock, net of withholdings	50,803,000	143,202,000	627,000	(12,286,000)
Amortization of deferred compensation	10,785,000	7,861,000	10,082,000	6,549,000
Ending Balance	10,519,239,000	10,457,651,000	10,240,447,000	10,229,738,000	10,519,239,000	10,240,447,000
Accumulated earnings less dividends
Changes in equity
Beginning Balance	306,861,000	350,777,000	128,166,000	188,609,000	350,777,000	188,609,000
Net income attributable to common stockholders	168,281,000	170,366,000	254,662,000	141,643,000
Change in redemption value of redeemable noncontrolling interest	(45,000)	(224,000)	(291,000)	(63,000)	(269,000)	354,000
Dividends declared to common stockholders ($1.52 per share)	(212,549,000)	(212,166,000)	203,472,000	(203,166,000)
Issuance of common stock, net of withholdings		(1,892,000)	1,000	1,143,000
Ending Balance	262,548,000	306,861,000	179,066,000	128,166,000	262,548,000	179,066,000
Accumulated other comprehensive loss
Changes in equity
Beginning Balance	(31,907,000)	(26,144,000)	(24,162,000)	(37,419,000)	(26,144,000)	(37,419,000)
(Loss) gain on cash flow hedges	(2,888,000)	(7,231,000)		11,501,000
Cash flow hedge losses reclassified to earnings	1,611,000	1,468,000	(1,455,000)	1,756,000
Ending Balance	(33,184,000)	(31,907,000)	$ (22,707,000)	$ (24,162,000)	(33,184,000)	$ (22,707,000)
Parent [Member]
Changes in equity
Beginning Balance	10,733,999,000	10,632,606,000			10,632,606,000
Net income attributable to common stockholders	168,281,000	170,366,000
(Loss) gain on cash flow hedges	(2,888,000)	(7,231,000)
Cash flow hedge losses reclassified to earnings	1,611,000	1,468,000
Change in redemption value of redeemable noncontrolling interest	(45,000)	(224,000)
Dividends declared to common stockholders ($1.52 per share)	(212,549,000)	(212,166,000)
Issuance of common stock, net of withholdings	50,806,000	141,319,000
Amortization of deferred compensation	10,785,000	7,861,000
Ending Balance	10,750,000,000	10,733,999,000			10,750,000,000
Noncontrolling Interest [Member]
Changes in equity
Beginning Balance	0	0			0
Noncontrolling interest contribution	530,000
Ending Balance	530,000	0			$ 530,000
Continuous Equity Program CEP IV
Class of Stock [Line Items]
Issuance of common stock, net	$ 0	$ 147,450,000