Guarantee of Securities of Subsidiaries Comprehensive Income (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Net Income	$ 669	$ 1,010	$ 1,423	$ 1,802
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax, Portion Attributable to Parent	1	0	3	(1)
Comprehensive Income	644	1,006	1,279	1,708
Comprehensive Income Attributable to Noncontrolling Interests	(8)	(10)	(15)	(18)
Comprehensive Income Attributable to KMEP	636	996	1,264	1,690
Parent Company [Member]
Net Income	661	1,000	1,407	1,783
Comprehensive Income	636	996	1,264	1,690
Comprehensive Income Attributable to Noncontrolling Interests	0	0	0	0
Comprehensive Income Attributable to KMEP	636	996	1,264	1,690
Subsidiary Issuer [Member]
Net Income	37	7	63	7
Comprehensive Income	37	7	63	7
Comprehensive Income Attributable to Noncontrolling Interests	0	0	0	0
Comprehensive Income Attributable to KMEP	37	7	63	7
Non-Guarantor Subsidiaries [Member]
Net Income	681	1,042	1,445	1,827
Comprehensive Income	656	1,038	1,301	1,733
Comprehensive Income Attributable to Noncontrolling Interests	8	(10)	(15)	18
Comprehensive Income Attributable to KMEP	648	1,028	1,286	1,715
Consolidation, Eliminations [Member]
Net Income	(710)	(1,039)	(1,492)	(1,815)
Comprehensive Income	(685)	(1,035)	(1,349)	(1,722)
Comprehensive Income Attributable to Noncontrolling Interests	0	0	0	0
Comprehensive Income Attributable to KMEP	(685)	(1,035)	(1,349)	(1,722)
Consolidated Entity Excluding Variable Interest Entities (VIE) [Member]
Net Income	669	1,010	1,423	1,802
Comprehensive Income	644	1,006	1,279	1,708
Comprehensive Income Attributable to Noncontrolling Interests	8	(10)	(15)	18
Comprehensive Income Attributable to KMEP	$ 636	$ 996	$ 1,264	$ 1,690