Commitments and Contingencies (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Feb. 25, 2016
Commitments and Contingencies Disclosure [Abstract]
Standby letters of credit and guarantees outstanding	$ 272,000,000	$ 423,000,000
Subsidiary payment obligations demand for payment				$ 0
Total Minimum Commitments [Abstract]
2016	1,275,650,000
2017	994,328,000
2018	781,299,000
2019	547,299,000
2020	431,221,000
2021 and beyond	900,961,000
Total Minimum Commitments	4,930,758,000
Rental expenses associated with existing leases	$ 229,000,000	$ 237,000,000	$ 191,000,000