Restructuring Costs Schedule of Restructuring Costs by Line of Business (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Restructuring Cost and Reserve [Line Items]
Estimated restructuring costs	$ 7.9
Restructuring costs incurred to date	7.9
Restructuring Charges	0	0.9	7.0
One-time Termination Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Estimated restructuring costs	3.6
Restructuring costs incurred to date	3.6
Restructuring Charges	0	0.5	3.1
Employee Relocation [Member]
Restructuring Cost and Reserve [Line Items]
Estimated restructuring costs	3.7
Restructuring costs incurred to date	3.7
Restructuring Charges	0	0.4	3.3
Facility Closing [Member]
Restructuring Cost and Reserve [Line Items]
Estimated restructuring costs	0.6
Restructuring costs incurred to date	0.6
Restructuring Charges	0	0	0.6
QEP Energy [Member]
Restructuring Cost and Reserve [Line Items]
Estimated restructuring costs	7.6
Restructuring costs incurred to date	7.6
Restructuring Charges	0	0.8	6.8
QEP Energy [Member] | One-time Termination Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Estimated restructuring costs	3.3
Restructuring costs incurred to date	3.3
Restructuring Charges	0	0.4	2.9
QEP Energy [Member] | Employee Relocation [Member]
Restructuring Cost and Reserve [Line Items]
Estimated restructuring costs	3.7
Restructuring costs incurred to date	3.7
Restructuring Charges	0	0.4	3.3
QEP Energy [Member] | Facility Closing [Member]
Restructuring Cost and Reserve [Line Items]
Estimated restructuring costs	0.6
Restructuring costs incurred to date	0.6
Restructuring Charges	0	0	0.6
QEP Marketing [Member]
Restructuring Cost and Reserve [Line Items]
Estimated restructuring costs	0.3
Restructuring costs incurred to date	0.3
Restructuring Charges	0	0.1	0.2
QEP Marketing [Member] | One-time Termination Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Estimated restructuring costs	0.3
Restructuring costs incurred to date	0.3
Restructuring Charges	$ 0	$ 0.1	$ 0.2