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Principles of Consolidation And Other Matters (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Operating funds related to regulatory requirements or as collateral under captive insurance arrangements	$ 203,000,000		$ 203,000,000
Effective tax rate	27.90%	29.60%	28.40%	28.90%
Unrecognized tax benefits	$ 77,000,000		$ 77,000,000		$ 97,000,000
Minimum [Member]
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Reasonably possible decrease in unrecognized tax benefits	0		0
Maximum [Member]
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Reasonably possible decrease in unrecognized tax benefits	$ 9,000,000		$ 9,000,000