Contingencies (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Environmental Contingencies
Liability recorded for projected environmental remediation costs	$ 14,000,000
Guarantees Letters Of Credit [Abstract]
The range of expiration dates of guarantees made by the Parent Company	The expiration dates of these guarantees vary from less than one year to more than 14 years.
Litigation Contingencies
Aggregate reserves for claims deemed both probable and reasonably estimable	321,000,000	363,000,000
Loss Contingency Range Of Possible Loss Minimum	881,000,000
Loss Contingency Range Of Possible Loss Maximum	1,600,000,000
Guarantees
Contingent Contractual Obligations [Line Items]
Amount	568,000,000
Number of Agreements	19
Letters of credit under secured credit facility
Contingent Contractual Obligations [Line Items]
Amount	5,000,000
Number of Agreements	6
Cash Collateralized Letters Of Credit [Member]
Contingent Contractual Obligations [Line Items]
Amount	$ 215,000,000
Number of Agreements	9