Reclassifications From Accumulated Other Comprehensive Income (Components Of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, December 31, 2014	$ 62
Other comprehensive income (loss) before reclassifications	18
Amounts reclassified from/to other comprehensive income	(128)
Net current-period other comprehensive income (loss)	(110)	$ 66	$ (154)
Ending balance, December 31, 2015	(48)	62
Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, December 31, 2014	98
Other comprehensive income (loss) before reclassifications	29
Amounts reclassified from/to other comprehensive income	(127)
Net current-period other comprehensive income (loss)	$ (98)
Ending balance, December 31, 2015		98
Pension And Other Postretirement [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, December 31, 2014	$ (24)
Amounts reclassified from/to other comprehensive income	(1)
Net current-period other comprehensive income (loss)	(1)
Ending balance, December 31, 2015	(25)	(24)
Foreign Currency [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, December 31, 2014	(12)
Other comprehensive income (loss) before reclassifications	(11)
Net current-period other comprehensive income (loss)	(11)
Ending balance, December 31, 2015	$ (23)	$ (12)