Supplemental Cash Flow Information (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Decrease (increase) in:
Accounts receivable - trade		$ (679.0)	$ 1,279.3	$ 1,685.4
Accounts receivable - related parties		0.4	1.3	3.8
Inventories		(871.8)	(72.7)	(105.6)
Prepaid and other current assets		(49.3)	(59.1)	(74.6)
Other assets		(2.0)	(5.8)	18.7
Increase (decrease) in:
Accounts payable - trade		(21.5)	(52.9)	(141.0)
Accounts payable - related parties		21.0	(34.8)	(31.6)
Accrued product payables		1,193.3	(1,342.4)	(1,647.8)
Accrued interest		(11.4)	16.5	31.3
Other current liabilities		189.9	(67.1)	141.3
Other liabilities		49.5	14.4	11.9
Net effect of changes in operating accounts		(180.9)	(323.3)	(108.2)
Cash payments for interest, net of $168.2, $149.1 and $77.9 capitalized in 2016, 2015 and 2014, respectively		947.9	911.6	832.1
Capitalized interest	[1]	168.2	149.1	77.9
Cash payments for federal and state income taxes		18.7	17.5	16.1
Liability for construction in progress expenditures		124.3	472.8	372.8
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from asset sales and insurance recoveries		46.5	1,608.6	145.3
Net gains (losses) attributable to asset sales and insurance recoveries		2.5	(15.6)	102.1
Offshore Business [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from asset sales and insurance recoveries		0.0	1,527.7	0.0
Net gains (losses) attributable to asset sales and insurance recoveries		0.0	(12.3)	0.0
West Storage Facilities [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from asset sales and insurance recoveries		0.0	0.0	95.0
Net gains (losses) attributable to asset sales and insurance recoveries		0.0	0.0	95.0
Other Disposal of Assets [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from asset sales and insurance recoveries		46.5	80.9	50.3
Net gains (losses) attributable to asset sales and insurance recoveries		$ 2.5	$ (3.3)	$ 7.1

[1] Capitalized interest is a component of "Interest expense" as presented on our Statements of Consolidated Operations.