Derivative Financial Instruments - Contractual and Weighted-Average Interest Rates, Which Include the Effects of Hedges Related to Financial Instruments (Details) - Long-term debt	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Derivative [Line Items]
Contractual Rates	3.59%	3.44%	3.60%	3.45%
Rate Including Impact of Hedges	2.35%	2.64%	2.51%	2.66%