Contingencies And Commitments (Other Obligations) (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Recorded Unconditional Purchase Obligation [Line Items]
Purchase obligations due in 2012	$ 286
Purchase obligations due in 2013	300
Purchase obligations due in 2014	309
Purchase obligations due in 2015	309
Purchase obligations due in 2016	308
Purchase obligations due thereafter	6,234
Purchase obligations expenditures	227	129	87
Operating leases, expense	287	260	249
Long-term operating leases, minimum annual rentals due in 2012	246
Long-term operating leases, minimum annual rentals due in 2013	159
Long-term operating leases, minimum annual rentals due in 2014	126
Long-term operating leases, minimum annual rentals due in 2015	109
Long-term operating leases, minimum annual rentals due in 2016	86
Long-term operating leases, minimum annual rentals due thereafter	564
Guarantees, total amount committed	436
Letters of credit, total amount committed	334
Letters of credit, expiration date	2012
Guarantees of third-party obligations related to project financing	779
Total amount committed under outstanding surety bonds	183
Surety bonds, expiration date	2012
Energy, Raw Materials, And Other Goods And Services [Member]
Recorded Unconditional Purchase Obligation [Line Items]
Purchase obligations due in 2012	3,723
Purchase obligations due in 2013	2,198
Purchase obligations due in 2014	2,095
Purchase obligations due in 2015	1,830
Purchase obligations due in 2016	1,823
Purchase obligations due thereafter	$ 10,906
Maximum [Member]
Recorded Unconditional Purchase Obligation [Line Items]
Expiration date of unconditional purchase obligations for energy	2041
Guarantees, expiration date	2027
Minimum [Member]
Recorded Unconditional Purchase Obligation [Line Items]
Expiration date of unconditional purchase obligations for energy	2012
Guarantees, expiration date	2015