Borrowings Under Credit Facilities and Related Items (Details Textual)	1 Months Ended	9 Months Ended
	Oct. 31, 2014	Sep. 30, 2014 USD ($) Number	Sep. 30, 2014 CAD	Sep. 30, 2014 GBP (£)	Dec. 31, 2013 USD ($)	Sep. 30, 2013 USD ($)
Line Of Credit Facility [Line Items]
Unsecured line of credit arrangement		$ 2,500,000,000
Additional unsecured line of credit arrangement		1,000,000,000
Maximum aggregate commitment		3,500,000,000
Number of banks in consortium		28	28	28
Available to borrow in alternate currencies		500,000,000
Agent bank's prime rate of interest		1.204%	1.204%	1.204%
Interest Rate margin		1.05%	1.05%	1.05%
Annual facility fee for each bank based on commitment amount	0.20%	0.20%	0.20%	0.20%
Balance outstanding at quarter end		0	0	0	130,000,000	847,670,000
Term Loan Interest Rate Margin		1.15%	1.15%	1.15%
HCN Term Loan		500,000,000
HCN Canadian Denomiated Term Loan		$ 250,000,000