SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Summary of Significant Accounting Policies - Inventory (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014 MMbtu		Dec. 31, 2013 MMbtu
Natural Gas Volumes	34,311,000		42,843,000
Natural Gas Inventory	$ 105	[1]	$ 184	[1]
Inventory, Raw Materials and Supplies	14		19
Inventories	119		203
Energy Related Inventory	$ 119		$ 203

[1] Natural gas volumes held for operations at December 31, 2014 and 2013 were 34.3 TBtu and 42.8 TBtu, respectively.