Commitments And Contingencies (Details) $ in Millions	1 Months Ended	3 Months Ended			12 Months Ended
	May. 31, 2015 USD ($)	Apr. 04, 2015 USD ($)	Jan. 03, 2015 USD ($) case	Mar. 30, 2013 case	Jan. 03, 2015 USD ($) case	Jul. 31, 2015 lawsuit	Jul. 04, 2015 case lawsuit	Dec. 17, 2014 lawsuit
March 2010 Securities Class Action
Commitments And Contingencies
Settlement expense			$ 50
Estimated damages on alleged claims					$ 475
Proceeds from insurance settlement		$ 40
December 2012 Securities Litigation
Commitments And Contingencies
Number of cases consolidated | case				2
Riata Litigation
Commitments And Contingencies
Settlement expense			$ 15
Pending lawsuits			950		950		3
Number of claimants in lawsuit | case							886
Initial payment	$ 13
Number of lawsuits outstanding | lawsuit								70
Riata Litigation | Subsequent Event
Commitments And Contingencies
Number of lawsuits outstanding | lawsuit						4