Holly-Frontier Merger (Narrative) (Details) (USD $) Share data in Millions, except Per Share data, unless otherwise specified	1 Months Ended	12 Months Ended
	Jul. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Jul. 02, 2011
Business Acquisition [Line Items]
Shares converted at acquisition	102.8
Common stock to be issued per share of Frontier stock	0.4811
Aggregate consideration paid in connection with merger					$ 3,700,000,000
Market closing price, per share					$ 35.93
Merger transaction costs recognized			15,100,000
General and administrative expenses		128,101,000	120,114,000	70,839,000
Merger Related Integration And Severance Costs Member
Business Acquisition [Line Items]
General and administrative expenses			$ 26,500,000