v2.4.0.8
Risk Management Activities and Fair Value Measurements - Fair Value (Details) (USD $)
In Millions, unless otherwise specified
Sep. 30, 2014
Jun. 30, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Amortized Cost Basis $ 77 $ 39
Available-for-sale Securities, Debt Maturities, Rolling Year Two Through Five, Amortized Cost Basis 909 458
Liabilities, Fair Value Disclosure [Abstract]    
Long Term Debt, Current Maturities measured at Fair Value 2,651 4,400
US Treasury and Government [Member]
    
Assets, Fair Value Disclosure [Abstract]    
Investment securities 2,377 1,631
Other Investments [Member]
    
Assets, Fair Value Disclosure [Abstract]    
Investment securities 33 30
Corporate Bond Securities [Member]
    
Assets, Fair Value Disclosure [Abstract]    
Investment securities 983 497
Fair Value Measurement [Domain]
    
Assets, Fair Value Disclosure [Abstract]    
Investment securities 3,393 2,158
Fair Value, Inputs, Level 2 [Member]
    
Liabilities, Fair Value Disclosure [Abstract]    
Long-term Debt, Fair Value 1,681 1,682
Estimate of Fair Value, Fair Value Disclosure [Member]
    
Liabilities, Fair Value Disclosure [Abstract]    
Long-term Debt, Fair Value 23,992 26,429
Other Current Assets [Member]
    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale Securities, Amortized Cost Basis 150 0
Other Noncurrent Assets [Member]
    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale Securities, Amortized Cost Basis $ 2,248 $ 1,649