Inventory (Tables)

12 Months Ended

Dec. 31, 2015

Inventory Disclosure [Abstract]

Inventory Balance By Type

The following table summarizes the Company's inventory balances (in millions) as of the dates indicated:

December 31,	2015		2014
Fuel and other raw materials	$	343	$	357
Spare parts and supplies	332		345
Total	$	675	$	702