Subsequent Events (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended					12 Months Ended
		Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Dec. 31, 2015
Subsequent Event [Line Items]
Debt and Capital Lease Obligations		$ 12,249,238				$ 11,920,861	$ 12,249,238
Common Stock, Dividends, Per Share, Cash Paid		$ 0.885	$ 0.82	$ 0.82	$ 0.82	$ 1.1250
Dividend Declared [Member] | Common Stock [Member]
Subsequent Event [Line Items]
Dividends Payable, Date Declared							Feb. 18, 2016
Dividends Payable, Date to be Paid							Mar. 31, 2016
Dividends Payable, Date of Record							Mar. 18, 2016
Refinancings of Debt [Member] | Senior Unsecured 2016 Credit Facility [Domain]
Subsequent Event [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		$ 5,500,000					$ 5,500,000
Refinancings of Debt [Member] | Senior Unsecured 364-Day Revolving Credit Facility [Domain]
Subsequent Event [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		1,000,000					1,000,000
Refinancings of Debt [Member] | Senior Unsecured Term Loan A Facility Due January 2021 [Domain]
Subsequent Event [Line Items]
Debt and Capital Lease Obligations		2,000,000					2,000,000
Refinancings of Debt [Member] | 2016 Senior Unsecured Revolving Credit Revolver [Domain]
Subsequent Event [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		2,500,000					2,500,000
Refinancings of Debt [Member] | 2016 Senior Unsecured Notes [Domain]
Subsequent Event [Line Items]
Debt Instrument, Face Amount		1,500,000					1,500,000
Refinancings of Debt [Member] | 3.4% Senior Unsecured Notes Due 2021 [Domain]
Subsequent Event [Line Items]
Debt Instrument, Face Amount		$ 600,000					$ 600,000
Debt Instrument, Interest Rate, Stated Percentage	[1]	3.40%					3.40%
Refinancings of Debt [Member] | 4.45% Senior Unsecured Notes Due 2026 [Domain]
Subsequent Event [Line Items]
Debt Instrument, Face Amount		$ 900,000					$ 900,000
Debt Instrument, Interest Rate, Stated Percentage	[1],[2]	4.45%					4.45%
Refinancings of Debt [Member] | Senior Unsecured 2016 Credit Facility [Domain]
Subsequent Event [Line Items]
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum	[1],[2]						1.125%
Effective Percentage Rate Range, Maximum	[1],[2]						2.00%
Paid subsequent to year end [Member]
Subsequent Event [Line Items]
Common Stock, Dividends, Per Share, Cash Paid		$ 0.885

[1] Represents the weighted-average stated interest rate.

[2] The 2012 Revolver and tranche A term loans ("Tranche A Term Loans"), including the Incremental Tranche A Term Loans (as defined below) bear interest at a rate per annum equal to LIBOR plus a credit spread ranging from 1.5% to 2.25%, based on the CCOC total net leverage ratio. The Company pays a commitment fee of approximately 0.25% per annum on the undrawn available amount under the 2012 Revolver.