Fair values as of the balance sheet date of the net amount of all assets and liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 45

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958

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Balance Type:	debit
Period Type:	instant

- Definition

The amount of cash received during the period on settlement of a hedge.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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- Definition

Fair value as of the balance sheet date of derivative instrument not designated as hedging instrument and classified as an asset.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4B

-Subparagraph (c)(2)

-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5624163-113959

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- Definition

Amount of realized and unrealized gain of derivative instruments not designated or qualifying as hedging instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4C

-Subparagraph (e)

-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5624171-113959

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- Definition

Nominal energy measure used to calculate payments on a derivative instrument.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
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- Definition

Nominal volume used to calculate payments on a derivative instrument.

+ References

No definition available.

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Namespace Prefix:	us-gaap_
Data Type:	num:volumeItemType
Balance Type:	na
Period Type:	duration

- Definition

The gain recognized in earnings during the reporting period representing the amount of the cash flow hedges' ineffectiveness.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4C

-Subparagraph (d)(1)

-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5624171-113959

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Derivative Instruments and Hedging Activities (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Feb. 27, 2015
Derivative Line [Items]
Fair value of derivative assets	$ 174.8
Atlas Pipeline Partners [Member]
Derivative Line [Items]
Fair value of derivative assets		102.1
Fair value of derivative contracts received as component of derivative contract settlement	7.8
Mark-to-market gains	0.5
Ineffectiveness gains	1.0
Swaps [Member] \| Year 2015 [Member] \| Natural Gas [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (MMBtu per day)	125,439
Swaps [Member] \| Year 2015 [Member] \| NGL [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (Bbl per day)	5,928
Swaps [Member] \| Year 2015 [Member] \| Condensate [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (Bbl per day)	1,991
Swaps [Member] \| Year 2016 [Member] \| Natural Gas [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (MMBtu per day)	68,205
Swaps [Member] \| Year 2016 [Member] \| NGL [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (Bbl per day)	2,254
Swaps [Member] \| Year 2016 [Member] \| Condensate [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (Bbl per day)	1,082
Swaps [Member] \| Year 2017 [Member] \| Natural Gas [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (MMBtu per day)	23,082
Swaps [Member] \| Year 2017 [Member] \| NGL [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (Bbl per day)	658
Swaps [Member] \| Year 2017 [Member] \| Condensate [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (Bbl per day)	500
Basis Swaps [Member] \| Year 2015 [Member] \| Natural Gas [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (MMBtu per day)	23,782
Basis Swaps [Member] \| Year 2016 [Member] \| Natural Gas [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (MMBtu per day)	0
Basis Swaps [Member] \| Year 2017 [Member] \| Natural Gas [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (MMBtu per day)	0
Options [Member] \| Crude Oil [Member] \| Atlas Pipeline Partners [Member]
Derivative Line [Items]
Fair value of outstanding derivative contracts		$ 7.7
Options [Member] \| Year 2015 [Member] \| NGL [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (Bbl per day)	899
Options [Member] \| Year 2015 [Member] \| Condensate [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (Bbl per day)	1,198
Options [Member] \| Year 2016 [Member] \| NGL [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (Bbl per day)	790
Options [Member] \| Year 2016 [Member] \| Condensate [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (Bbl per day)	380
Options [Member] \| Year 2017 [Member] \| NGL [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (Bbl per day)	790
Options [Member] \| Year 2017 [Member] \| Condensate [Member]
Derivative Line [Items]
Notional volumes of commodity hedges (Bbl per day)	380