Derivative Financial Instruments - Contractual and Weighted-Average Interest Rates, Which Include the Effects of Hedges Related to Financial Instruments (Details) - Long-term debt	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015
Derivative [Line Items]
Contractual rates	3.40%	3.57%
Rate including impact of hedges	2.29%	2.42%

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_DerivativeLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration