Equity (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Changes in equity
Beginning Balance			$ 9,840,526
Net income attributable to common stockholders	$ 197,444	$ 172,324	435,377	$ 380,469
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax, Portion Attributable to Parent	(26,788)	(6)	(74,545)	(36)
Cash flow hedge loss reclassified to earnings	1,561	$ 1,433	2,935	$ 3,028
Change in redemption value of redeemable noncontrolling interest			(375)
Dividends declared to common stockholders			(370,533)
Issuance of common stock, net of withholdings			8,434
Amortization of deferred compensation			14,700
Ending Balance	9,856,519		9,856,519
Common stock
Changes in equity
Beginning Balance			1,370
Issuance of common stock, net of withholdings			3
Ending Balance	1,373		1,373
Additional paid-in capital
Changes in equity
Beginning Balance			10,068,532
Issuance of common stock, net of withholdings			9,719
Amortization of deferred compensation			14,700
Ending Balance	10,092,951		10,092,951
Accumulated earnings less dividends
Changes in equity
Beginning Balance			(197,989)
Net income attributable to common stockholders			435,377
Change in redemption value of redeemable noncontrolling interest			(375)
Dividends declared to common stockholders			(370,533)
Issuance of common stock, net of withholdings			(1,288)
Ending Balance	(134,808)		(134,808)
Accumulated other comprehensive loss
Changes in equity
Beginning Balance			(31,387)
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax, Portion Attributable to Parent			(74,545)
Cash flow hedge loss reclassified to earnings			2,935
Ending Balance	$ (102,997)		$ (102,997)