Pension And Postretirement Benefits (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2016	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Combined net pension and postretirement cost increase (decrease)	$ (57)		$ (116)
Pension Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Net supplemental retirement pension benefits costs	24	$ 21	47	$ 41
Pension Contribution Date						Dec. 31, 2013
Required contribution to pension plans			280		$ 560
Annualized cash distributions to be received by the trust/pension					$ 175
Value of entity's noncash contribution to it's defined benefit plans	$ 8,704		$ 8,704