Employee Benefits (Details 2) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Health Care and Life Insurance
Health care benefit expenses	$ 204ctq_HealthCareBenefitExpense	$ 223ctq_HealthCareBenefitExpense	$ 221ctq_HealthCareBenefitExpense

Represents the health care benefit expenses for the active employees health care plan.

No definition available.

Name:	ctq_HealthCareBenefitExpense
Namespace Prefix:	ctq_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration