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
Valuation and qualifying accounts
Balance at Beginning of Period	$ 573	$ 558	$ 559
Charged to Costs and Expenses	63	113	90
Charged to Other Accounts	4		14
Deductions	(144)	(98)	(105)
Balance at End of Period	496	573	558
Valuation and qualifying accounts, classified as current	101	98	100
Allowance for doubtful accounts
Valuation and qualifying accounts
Balance at Beginning of Period	16	16	19
Charged to Costs and Expenses	1	0
Deductions			(3)
Balance at End of Period	17	16	16
Environmental
Valuation and qualifying accounts
Balance at Beginning of Period	344	360	366
Charged to Costs and Expenses	60	56	53
Charged to Other Accounts			14
Deductions	(74)	(72)	(73)
Balance at End of Period	330	344	360
Litigation, tax and other reserves
Valuation and qualifying accounts
Balance at Beginning of Period	229	198	193
Charged to Costs and Expenses	3	57	37
Charged to Other Accounts	4
Deductions	(70)	(26)	(32)
Balance at End of Period	$ 166	$ 229	$ 198