Quarterly report pursuant to Section 13 or 15(d)

Summary of Significant Accounting Policies (Details)

v2.4.1.9
Summary of Significant Accounting Policies (Details) (USD $)
In Millions, except Share data, unless otherwise specified
3 Months Ended
Mar. 31, 2015
Derivative Financial Instruments  
Fair value of commodity derivative contracts $ 2,200us-gaap_PriceRiskDerivativeAssetsAtFairValue
Earnings per share  
Other comprehensive income (loss) 0us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent
Dilutive shares attributable to non-vested restricted stock and restricted stock unit awards and stock options. 5,286us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements
Citigroup  
Derivative Financial Instruments  
Fair value of commodity derivative contracts 406us-gaap_PriceRiskDerivativeAssetsAtFairValue
/ us-gaap_CounterpartyNameAxis
= ar_CitigroupMember
Barclays  
Derivative Financial Instruments  
Fair value of commodity derivative contracts 388us-gaap_PriceRiskDerivativeAssetsAtFairValue
/ us-gaap_CounterpartyNameAxis
= ar_BarclaysMember
JP Morgan  
Derivative Financial Instruments  
Fair value of commodity derivative contracts 354us-gaap_PriceRiskDerivativeAssetsAtFairValue
/ us-gaap_CounterpartyNameAxis
= ar_JPMorganMember
Credit Suisse  
Derivative Financial Instruments  
Fair value of commodity derivative contracts 313us-gaap_PriceRiskDerivativeAssetsAtFairValue
/ us-gaap_CounterpartyNameAxis
= ar_CreditSuisseMember
Wells Fargo  
Derivative Financial Instruments  
Fair value of commodity derivative contracts 258us-gaap_PriceRiskDerivativeAssetsAtFairValue
/ us-gaap_CounterpartyNameAxis
= ar_WellsFargoMember
BNP Paribas  
Derivative Financial Instruments  
Fair value of commodity derivative contracts 217us-gaap_PriceRiskDerivativeAssetsAtFairValue
/ us-gaap_CounterpartyNameAxis
= ar_BNPParibasMember
Scotiabank  
Derivative Financial Instruments  
Fair value of commodity derivative contracts 131us-gaap_PriceRiskDerivativeAssetsAtFairValue
/ us-gaap_CounterpartyNameAxis
= ar_ScotiabankMember
Toronto Dominion Bank  
Derivative Financial Instruments  
Fair value of commodity derivative contracts 49us-gaap_PriceRiskDerivativeAssetsAtFairValue
/ us-gaap_CounterpartyNameAxis
= ar_TorontoDominionBankMember
Fifth Third Bank  
Derivative Financial Instruments  
Fair value of commodity derivative contracts 37us-gaap_PriceRiskDerivativeAssetsAtFairValue
/ us-gaap_CounterpartyNameAxis
= ar_FifthThirdBankMember
Canadian Imperial Bank of Commerce [Member]  
Derivative Financial Instruments  
Fair value of commodity derivative contracts 7us-gaap_PriceRiskDerivativeAssetsAtFairValue
/ us-gaap_CounterpartyNameAxis
= ar_CanadianImperialBankOfCommerceMember
Bank of Montreal  
Derivative Financial Instruments  
Fair value of commodity derivative contracts 4us-gaap_PriceRiskDerivativeAssetsAtFairValue
/ us-gaap_CounterpartyNameAxis
= ar_BankOfMontrealMember
Morgan Stanley [Member]  
Derivative Financial Instruments  
Fair value of commodity derivative contracts $ 3us-gaap_PriceRiskDerivativeAssetsAtFairValue
/ us-gaap_CounterpartyNameAxis
= ar_MorganStanleyMember