Variable Interest Entities (Details) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended			6 Months Ended	1 Months Ended			1 Months Ended			6 Months Ended
	Jun. 30, 2012 USD ($)	Jun. 30, 2011 USD ($)	Jun. 30, 2012 USD ($)	Jun. 30, 2011 USD ($)	Dec. 31, 2011 USD ($)	Jun. 30, 2012 Limited Liability Company I [Member]	Apr. 30, 2010 Low-Income Housing Properties [Member] USD ($)	Jun. 30, 2012 Low-Income Housing Properties [Member] USD ($)	Dec. 31, 2011 Low-Income Housing Properties [Member] USD ($)	Jan. 31, 2011 Investment in Refined Coal Facility [Member] USD ($)	Jun. 30, 2012 Investment in Refined Coal Facility [Member] USD ($)	Dec. 31, 2011 Investment in Refined Coal Facility [Member] USD ($)	Jun. 30, 2012 Investment in Recycling and Waste to Energy [Member] USD ($)	Jun. 30, 2012 Investment in Recycling and Waste to Energy [Member] GBP (£)	Jun. 30, 2012 Limited Liability Company II [Member]	Jun. 30, 2012 Limited Liability Company II [Member] Limited Liability Company I [Member] USD ($)	Dec. 31, 2011 Limited Liability Company II [Member] Limited Liability Company I [Member] USD ($)	Dec. 31, 2000 Limited Liability Company II [Member] Limited Liability Company I [Member] USD ($)
Variable Interest Entities (Textual) [Abstract]
Percentage of ownership in LLC's						0.50%							50.00%	50.00%	0.25%
Percentage of variable interest entities owned by other companies						99.50%									99.75%
Total initial investment by other companies																		$ 167
Reporting entity percentage of interest in earnings of variable interest entity after achieving targeted returns																80.00%
Other companies percentage of interest in earnings of variable interest entity after achieving targeted returns																20.00%
Consolidated variable interest entity carrying amount of asset																302	308
Noncontrolling interests	319		319		320											248	246
Investment balance								166	178		30	35	1
Expected cost to construct Waste-to-Energy LLC facility													314	200
Total commitment													90	57
Note receivables balance from the LLC													11	7
Consideration for investment							221
Cash payments to acquire equity method investment							6			48
Value of notes payable included in consideration for investment							215
Equity method investments debt balance								164	176
Variable Interest Entities (Additional Details) [Abstract]
Under the LLC agreements, the LLC shall be dissolved upon the occurrence of any of the following events			(i) A written decision of all members of the LLCs; (ii) December31, 2063; (iii) a court's dissolution of the LLCs; or (iv) the LLCs ceasing to own any interest in the waste-to-energy facilities.
Expense recognized for other companies' noncontrolling interests in LLCs earnings	12	12	25	25
Carrying value of restricted trust funds and escrow accounts for which company is not the sole beneficiary specifically for future settlement of landfill and environmental remediation liabilities	109		109		107
Variable interest entities primary beneficiary trust fair value assets	$ 120		$ 120		$ 123