Segment Reporting (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Segment Reporting Information [Line Items]
Revenues		$ 3,272	$ 3,692
Gross Profit	[1]	108	370
Operating Expenses		190	218
Operating income		(82)	152
Interest expense, net		(44)	(42)
Other income (expense), net		0	(3)
Net income (loss)		(128)	109
Depreciation, amortization and accretion		45	45
Non-cash unit-based compensation expense		4	3
Loss on disposal of assets and impairment charges		2	48
Unrealized loss (gain) on commodity derivatives		6	(6)
Inventory adjustments		227	(93)
Equity in earnings of unconsolidated affiliate		(1)	0
Adjusted EBITDA related to unconsolidated affiliate		2	0
Other non-cash adjustments		5	7
Income (loss) from operations before income taxes		(125)	107
Income tax expense (benefit)		3	(2)
Adjusted EBITDA		209	153
Capital expenditures		41	26
Assets		4,977		$ 5,438
Fuel Distribution and Marketing [Member]
Segment Reporting Information [Line Items]
Revenues		3,080	3,493
All Other [Member]
Segment Reporting Information [Line Items]
Revenues		192	199
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenues			(396)
Motor Fuel Sales [Member]
Segment Reporting Information [Line Items]
Revenues		3,166	3,583
Gross Profit	[1]	21	285
Motor Fuel Sales [Member] | All Other [Member]
Segment Reporting Information [Line Items]
Revenues		127	141
Non Motor Fuel Sales [Member]
Segment Reporting Information [Line Items]
Revenues		71	74
Intersegment Sales [Member] | Fuel Distribution and Marketing [Member]
Segment Reporting Information [Line Items]
Revenues			364
Intersegment Sales [Member] | All Other [Member]
Segment Reporting Information [Line Items]
Revenues			32
Intersegment Sales [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenues		(293)	(396)
Lease Income [Member]
Segment Reporting Information [Line Items]
Revenues		35	35
Gross Profit	[1]	35	35
Lease Income [Member] | Fuel Distribution and Marketing [Member]
Segment Reporting Information [Line Items]
Revenues		30	32
Lease Income [Member] | All Other [Member]
Segment Reporting Information [Line Items]
Revenues		5	3
Non Motor Fuel [Member]
Segment Reporting Information [Line Items]
Gross Profit	[1]	52	50
Non Motor Fuel [Member] | Fuel Distribution and Marketing [Member]
Segment Reporting Information [Line Items]
Revenues		11	19
Non Motor Fuel [Member] | All Other [Member]
Segment Reporting Information [Line Items]
Revenues		60	55
Including Intercompany [Member] | Fuel Distribution and Marketing [Member]
Segment Reporting Information [Line Items]
Revenues			3,857
Including Intercompany [Member] | All Other [Member]
Segment Reporting Information [Line Items]
Revenues			231
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenues		(293)
Intersegment Eliminations [Member] | Intersegment Sales [Member] | Fuel Distribution and Marketing [Member]
Segment Reporting Information [Line Items]
Revenues		293
Intersegment Eliminations [Member] | Intersegment Sales [Member] | All Other [Member]
Segment Reporting Information [Line Items]
Revenues		0
Operating Segments [Member] | Fuel Distribution and Marketing [Member]
Segment Reporting Information [Line Items]
Revenues		3,373
Gross Profit	[1]	35	307
Operating Expenses		155	135
Operating income		(120)	172
Interest expense, net		(38)	(36)
Other income (expense), net		0	3
Net income (loss)		(157)	137
Depreciation, amortization and accretion		37	34
Non-cash unit-based compensation expense		4	3
Loss on disposal of assets and impairment charges		0	(4)
Unrealized loss (gain) on commodity derivatives		(6)	6
Inventory adjustments		226	(93)
Equity in earnings of unconsolidated affiliate		(1)	0
Adjusted EBITDA related to unconsolidated affiliate		2	0
Other non-cash adjustments		5	1
Income (loss) from operations before income taxes		(157)	139
Income tax expense (benefit)		0	2
Adjusted EBITDA		160	118
Capital expenditures		25	20
Assets		3,784		4,189
Operating Segments [Member] | All Other [Member]
Segment Reporting Information [Line Items]
Revenues		192
Gross Profit	[1]	73	63
Operating Expenses		35	83
Operating income		38	(20)
Interest expense, net		(6)	(6)
Other income (expense), net			(6)
Net income (loss)		29	(28)
Depreciation, amortization and accretion		8	11
Non-cash unit-based compensation expense		0	0
Loss on disposal of assets and impairment charges		(2)	(44)
Unrealized loss (gain) on commodity derivatives		0	0
Inventory adjustments		1	0
Equity in earnings of unconsolidated affiliate		0	0
Adjusted EBITDA related to unconsolidated affiliate		0	0
Other non-cash adjustments		0	6
Income (loss) from operations before income taxes		32	(32)
Income tax expense (benefit)		3	(4)
Adjusted EBITDA		49	35
Capital expenditures		16	6
Assets		1,193		$ 1,249
Operating Segments [Member] | Motor Fuel Sales [Member] | Fuel Distribution and Marketing [Member]
Segment Reporting Information [Line Items]
Gross Profit	[1]	(6)	258
Operating Segments [Member] | Motor Fuel Sales [Member] | All Other [Member]
Segment Reporting Information [Line Items]
Gross Profit	[1]	27	27
Operating Segments [Member] | Lease Income [Member] | Fuel Distribution and Marketing [Member]
Segment Reporting Information [Line Items]
Gross Profit	[1]	30	32
Operating Segments [Member] | Lease Income [Member] | All Other [Member]
Segment Reporting Information [Line Items]
Gross Profit	[1]	5	3
Operating Segments [Member] | Non Motor Fuel [Member] | Fuel Distribution and Marketing [Member]
Segment Reporting Information [Line Items]
Gross Profit	[1]	11	17
Operating Segments [Member] | Non Motor Fuel [Member] | All Other [Member]
Segment Reporting Information [Line Items]
Gross Profit	[1]	41	33
External Revenue [Member] | Motor Fuel Sales [Member]
Segment Reporting Information [Line Items]
Revenues		3,166	3,583
External Revenue [Member] | Motor Fuel Sales [Member] | Fuel Distribution and Marketing [Member]
Segment Reporting Information [Line Items]
Revenues		3,039	3,442
External Revenue [Member] | Motor Fuel Sales [Member] | All Other [Member]
Segment Reporting Information [Line Items]
Revenues		127	141
External Revenue [Member] | Non Motor Fuel Sales [Member] | Fuel Distribution and Marketing [Member]
Segment Reporting Information [Line Items]
Revenues		11
External Revenue [Member] | Non Motor Fuel Sales [Member] | All Other [Member]
Segment Reporting Information [Line Items]
Revenues		60
External Revenue [Member] | Lease Income [Member]
Segment Reporting Information [Line Items]
Revenues		35	35
External Revenue [Member] | Lease Income [Member] | Fuel Distribution and Marketing [Member]
Segment Reporting Information [Line Items]
Revenues		30	32
External Revenue [Member] | Lease Income [Member] | All Other [Member]
Segment Reporting Information [Line Items]
Revenues		5	3
External Revenue [Member] | Non Motor Fuel [Member]
Segment Reporting Information [Line Items]
Revenues		$ 71	74
External Revenue [Member] | Non Motor Fuel [Member] | Fuel Distribution and Marketing [Member]
Segment Reporting Information [Line Items]
Revenues			19
External Revenue [Member] | Non Motor Fuel [Member] | All Other [Member]
Segment Reporting Information [Line Items]
Revenues			$ 55

[1] Excludes depreciation, amortization and accretion.