Retirement Benefits (Changes In The Fair Value Of Plan Assets Classified As Level 3) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Real estate
Change in plan assets:
Fair value of plan assets at beginning of year	$ 147	$ 131
Actual Return on Plan Assets Related to Assets Still Held at the Reporting Date	14	11
Purchases, Sales and Settlements, net	7	5
Fair value of plan assets at end of year	168	147
Private equity
Change in plan assets:
Fair value of plan assets at beginning of year	13	15
Actual Return on Plan Assets Related to Assets Still Held at the Reporting Date	(9)	(9)
Actual Return on Plan Assets Related to Assets Sold During the Period	9	10
Purchases, Sales and Settlements, net	(5)	(3)
Fair value of plan assets at end of year	$ 8	$ 13