v2.4.0.6
Assets and Liabilities with Recurring Fair Value Measurements (Details) (USD $)
In Millions, unless otherwise specified
Mar. 31, 2013
Dec. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash equivalents $ 1,124 [1] $ 1,502 [1]
Margin deposits 257 [2] 196 [2]
Commodity futures contracts 594 385
Commodity forward contracts 64 [3] 48 [3]
Interest Rate Swap Assets, Fair Value Disclosure 5 4
Total assets 2,044 2,135
Margin deposits held by us posted by our counterparties 1 [2],[4] 11 [2],[4]
Commodity futures contracts 655 424
Commodity forward contracts 41 [3] 26 [3]
Interest rate swaps 188 200
Liabilities, Fair Value Disclosure 885 661
Fair Value, Inputs, Level 1 [Member]
    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash equivalents 1,124 [1] 1,502 [1]
Margin deposits 257 196
Commodity futures contracts 594 385
Commodity forward contracts 0 [3] 0 [3]
Interest Rate Swap Assets, Fair Value Disclosure 0 0
Total assets 1,975 2,083
Margin deposits held by us posted by our counterparties 1 11
Commodity futures contracts 655 424
Commodity forward contracts 0 [3] 0 [3]
Interest rate swaps 0 0
Liabilities, Fair Value Disclosure 656 435
Fair Value, Inputs, Level 2 [Member]
    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash equivalents 0 [1] 0 [1]
Margin deposits 0 0
Commodity futures contracts 0 0
Commodity forward contracts 43 [3] 24 [3]
Interest Rate Swap Assets, Fair Value Disclosure 5 4
Total assets 48 28
Margin deposits held by us posted by our counterparties 0 0
Commodity futures contracts 0 0
Commodity forward contracts 33 [3] 18 [3]
Interest rate swaps 188 200
Liabilities, Fair Value Disclosure 221 218
Fair Value, Inputs, Level 3 [Member]
    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash equivalents 0 [1] 0 [1]
Margin deposits 0 0
Commodity futures contracts 0 0
Commodity forward contracts 21 [3] 24 [3]
Interest Rate Swap Assets, Fair Value Disclosure 0 0
Total assets 21 24
Margin deposits held by us posted by our counterparties 0 0
Commodity futures contracts 0 0
Commodity forward contracts 8 [3] 8 [3]
Interest rate swaps 0 0
Liabilities, Fair Value Disclosure $ 8 $ 8
Physical Power [Member]
    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fair Value Inputs Quantitative Information Power 8,000,000.00 11,000,000.00
Minimum [Member]
    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fair Value Inputs Quantitative Information Power 31.75 23.75
Maximum [Member]
    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fair Value Inputs Quantitative Information Power 56.00 53.82
[1] As of March 31, 2013 and December 31, 2012, we had cash equivalents of $952 million and $1,274 million included in cash and cash equivalents and $172 million and $228 million included in restricted cash, respectively.
[2] Balances are subject to master netting arrangements and presented on a gross basis on our Consolidated Condensed Balance Sheets. We do not offset fair value amounts recognized for derivative instruments executed with the same counterparty under a master netting arrangement for financial statement presentation, and we do not offset amounts recognized for the right to reclaim, or the obligation to return, cash collateral with corresponding derivative instrument fair values.
[3] Includes OTC swaps and options.
[4] Included in other current liabilities on our Consolidated Condensed Balance Sheets.