Regulatory Assets and Liabilities Schedule of Regulatory Assets and Liabilities (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Regulatory Assets [Line Items]
Remaining Recovery Period of Regulatory Assets, Price Risk Management	6 years
Remaining Recovery Period of Regulatory Asset, Deferred Broker Settlements	1 year
Remaining Recovery Period of Regulatory Asset, Debt Reacquisition Costs	8 years
Price risk management	$ 13	$ 4
Deferred income taxes	16	20
remaining recovery period of regulatory assets, deferred capital projects	2 years
Current Regulatory Liabilities [Member]
Regulatory Assets [Line Items]
Asset retirement removal costs	0	0
Proceeds from Legal Settlements	0	0
Asset retirement obligations	0	0
Other	1	12
Total regulatory liabilities	1	12
Noncurrent Regulatory Liabilities [Member]
Regulatory Assets [Line Items]
Asset retirement removal costs	747	692
Proceeds from Legal Settlements	41	0
Asset retirement obligations	39	39
Other	38	34
Total regulatory liabilities	865	765
Regulatory Assets, Current [Member]
Regulatory Assets [Line Items]
Price risk management	36	123
Pension and other postretirement plans	0	0
Deferred income taxes	0	0
Deferred broker settlements	12	20
Debt reacquisition costs	0	0
Deferred capital project	16	0
Other	2	1
Total regulatory assets	66	144
Noncurrent Regulatory Assets [Member]
Regulatory Assets [Line Items]
Price risk management	140	71
Pension and other postretirement plans	194	321
Deferred income taxes	76	80
Deferred broker settlements	1	1
Debt reacquisition costs	17	22
Deferred capital project	18	16
Other	18	13
Total regulatory assets	$ 464	$ 524