Stockholder's Equity (Details 5) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Summary of dividend payments
Dividends declared and paid per common share	$ 0.795	$ 0.765	$ 2.385	$ 2.295
Common stock cash dividends			$ 708,923,000	$ 618,992,000
Total dividends paid			757,980,000	668,797,000
Series H Preferred Stock [Member]
Summary of dividend payments
Dividends declared and paid per preferred share			$ 0.0079	$ 2.1438
Preferred stock cash dividends			1,000	750,000
Series I Preferred Stock [Member]
Summary of dividend payments
Dividends declared and paid per preferred share			$ 2.4375	$ 2.4375
Preferred stock cash dividends			35,040,000	35,039,000
Series J Preferred Stock [Member]
Summary of dividend payments
Dividends declared and paid per preferred share			$ 1.2189	$ 1.2189
Preferred stock cash dividends			$ 14,016,000	$ 14,016,000