Regulatory Matters Regulatory Liabilities (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012
Regulatory Liabilities [Line Items]
Current regulatory liabilities	$ 55		$ 62
Noncurrent regulatory liabilities	879		851
Total regulatory liabilities	934		913
Cost of removal [Member]
Regulatory Liabilities [Line Items]
Weighted Average Remaining Life	33 years	[1]
Noncurrent regulatory liabilities	843		810
Total regulatory liabilities	843	[1]	810	[1]
Deferred income taxes [Member]
Regulatory Liabilities [Line Items]
Weighted Average Remaining Life	Various
Total regulatory liabilities	21		21
Other [Member]
Regulatory Liabilities [Line Items]
Weighted Average Remaining Life	Various
Total regulatory liabilities	$ 70		$ 82

[1] Amounts represent estimated costs, as accrued through depreciation rates and exclusive of ARO liabilities, of removing property, plant and equipment in accordance with accepted regulatory practices. Amounts are deducted from rate base or otherwise accrue a carrying cost.