SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Materials and supplies inventory allowance
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	$ 27		$ 26		$ 26
Additions Charged to Cost and Expense	22		7		4
Additons Charged to Other Accounts	0		0		0
Other Additions (Deductions)	(25)	[1]	(6)	[1]	(4)	[1]
Balance at End of Year	24		27		26
Valuation allowance for deferred tax assets
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	2,443		2,393		2,226
Additions Charged to Cost and Expense	42		49		146
Additons Charged to Other Accounts	0		1		21
Other Additions (Deductions)	0		0		0
Balance at End of Year	2,485		2,443		2,393
Reserves for non-income taxes
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	80		73		73
Additions Charged to Cost and Expense	35		21		12
Additons Charged to Other Accounts	(1)		(2)		(2)
Other Additions (Deductions)	(36)	[2]	(12)	[2]	(10)	[2]
Balance at End of Year	$ 78		$ 80		$ 73

[1] Primarily represents write-offs of obsolete materials and supplies inventories.

[2] Represents amounts paid or adjustments to reserves based on revised estimates.