Consolidating Guarantor Financial Information Condensed Income Statement (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Revenues	$ 999	$ 863
Operating costs, expenses, and other	968	841
Operating income (loss)	31	22
Income from unconsolidated affiliates	50	43
Interest expense, net	(82)	(56)
Equity in consolidated subsidiaries	0	0
Other income and deductions, net	3	2
Income before income taxes	2	11
Income tax expense (benefit)	5	(1)
Net (loss) income	(3)	12
Net income attributable to noncontrolling interest	(4)	(3)
Net (loss) income attributable to Regency Energy Partners LP	(7)	9
Total other comprehensive income	0	0
Comprehensive (loss) income	(3)	12
Comprehensive income attributable to noncontrolling interest	4	3
Comprehensive (loss) income attributable to Regency Energy Partners LP	(7)	9
Parent Company [Member]
Revenues	0	0
Operating costs, expenses, and other	0	0
Operating income (loss)	0	0
Income from unconsolidated affiliates	0	0
Interest expense, net	(76)	(49)
Equity in consolidated subsidiaries	74	51
Other income and deductions, net	2	(1)
Income before income taxes	0	1
Income tax expense (benefit)	5	0
Net (loss) income	(5)	1
Net income attributable to noncontrolling interest	0	0
Net (loss) income attributable to Regency Energy Partners LP	(5)	1
Total other comprehensive income	0	0
Comprehensive (loss) income	(5)	1
Comprehensive income attributable to noncontrolling interest	0	0
Comprehensive (loss) income attributable to Regency Energy Partners LP	(5)	1
Guarantor Subsidiaries [Member]
Revenues	982	848
Operating costs, expenses, and other	961	834
Operating income (loss)	21	14
Income from unconsolidated affiliates	50	43
Interest expense, net	(6)	(7)
Equity in consolidated subsidiaries	0	0
Other income and deductions, net	1	3
Income before income taxes	66	53
Income tax expense (benefit)	0	(2)
Net (loss) income	66	55
Net income attributable to noncontrolling interest	0	(3)
Net (loss) income attributable to Regency Energy Partners LP	66	52
Total other comprehensive income	0	0
Comprehensive (loss) income	66	55
Comprehensive income attributable to noncontrolling interest	0	3
Comprehensive (loss) income attributable to Regency Energy Partners LP	66	52
Non-Guarantor Subsidiaries [Member]
Revenues	17	15
Operating costs, expenses, and other	9	7
Operating income (loss)	8	8
Income from unconsolidated affiliates	0	0
Interest expense, net	0	0
Equity in consolidated subsidiaries	0	0
Other income and deductions, net	0	0
Income before income taxes	8	8
Income tax expense (benefit)	0	1
Net (loss) income	8	7
Net income attributable to noncontrolling interest	0	0
Net (loss) income attributable to Regency Energy Partners LP	8	7
Total other comprehensive income	0	0
Comprehensive (loss) income	8	7
Comprehensive income attributable to noncontrolling interest	0	0
Comprehensive (loss) income attributable to Regency Energy Partners LP	8	7
Consolidation, Eliminations [Member]
Revenues	0	0
Operating costs, expenses, and other	(2)	0
Operating income (loss)	2	0
Income from unconsolidated affiliates	0	0
Interest expense, net	0	0
Equity in consolidated subsidiaries	(74)	(51)
Other income and deductions, net	0	0
Income before income taxes	(72)	(51)
Income tax expense (benefit)	0	0
Net (loss) income	(72)	(51)
Net income attributable to noncontrolling interest	(4)	0
Net (loss) income attributable to Regency Energy Partners LP	(76)	(51)
Total other comprehensive income	0	0
Comprehensive (loss) income	(72)	(51)
Comprehensive income attributable to noncontrolling interest	4	0
Comprehensive (loss) income attributable to Regency Energy Partners LP	$ (76)	$ (51)