Fair Value Measurements (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011
Additional disclosure: [Abstract]
Fair Value, Level 1 to level 2 Transfers, Amount	$ 0		$ 0
Fair Value, Level 2 to level 1 Transfers, Amount	0		0
Carrying Amount [Member]
Additional disclosure: [Abstract]
Notes receivable and other	95		57
Long-term debt, including current portion	(10,734)	[1]	(8,718)	[1]
Guarantee	(33)		(34)
Carrying Amount [Member] | Former Venezuela Operations [Member]
Additional disclosure: [Abstract]
Notes Receivable, Fair Value Disclosure	49
Fair Value [Member]
Additional disclosure: [Abstract]
Notes receivable and other	138		57
Long-term debt, including current portion	(12,388)	[1]	(10,043)	[1]
Guarantee	(31)		(32)
Fair Value [Member] | Former Venezuela Operations [Member]
Additional disclosure: [Abstract]
Notes Receivable, Fair Value Disclosure	93
Level 1 [Member]
Additional disclosure: [Abstract]
Notes receivable and other	2
Long-term debt, including current portion	0	[1]
Guarantee	0
Level 2 [Member]
Additional disclosure: [Abstract]
Notes receivable and other	8
Long-term debt, including current portion	(12,388)	[1]
Guarantee	(31)
Level 3 [Member]
Additional disclosure: [Abstract]
Notes receivable and other	128
Long-term debt, including current portion	0	[1]
Guarantee	0
Fair Value, Measurements, Recurring [Member] | Carrying Amount [Member]
Measured on a recurring basis: [Abstract]
ARO Trust investments	18		25
Available-for-sale equity securities			24
Fair Value, Measurements, Recurring [Member] | Carrying Amount [Member] | Not Designated as Hedging Instrument [Member]
Measured on a recurring basis: [Abstract]
Energy derivatives assets	5		1
Energy derivative liabilities	(1)
Fair Value, Measurements, Recurring [Member] | Fair Value [Member]
Measured on a recurring basis: [Abstract]
ARO Trust investments	18		25
Available-for-sale equity securities			24
Fair Value, Measurements, Recurring [Member] | Fair Value [Member] | Not Designated as Hedging Instrument [Member]
Measured on a recurring basis: [Abstract]
Energy derivatives assets	5		1
Energy derivative liabilities	(1)
Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Measured on a recurring basis: [Abstract]
ARO Trust investments	18		25
Available-for-sale equity securities			24
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Not Designated as Hedging Instrument [Member]
Measured on a recurring basis: [Abstract]
Energy derivatives assets	0		1
Energy derivative liabilities	0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Measured on a recurring basis: [Abstract]
ARO Trust investments	0		0
Available-for-sale equity securities			0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Not Designated as Hedging Instrument [Member]
Measured on a recurring basis: [Abstract]
Energy derivatives assets	0		0
Energy derivative liabilities	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member]
Measured on a recurring basis: [Abstract]
ARO Trust investments	0		0
Available-for-sale equity securities			0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Not Designated as Hedging Instrument [Member]
Measured on a recurring basis: [Abstract]
Energy derivatives assets	5		0
Energy derivative liabilities	$ (1)

[1] Excludes capital leases.