Retirement Benefits (Details 3) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Amounts recorded in accumulated other comprehensive loss (Table Amounts)
Unamortized benefit plan costs	$ (5,416)	$ (5,241)
Pension Benefits
Amounts recorded in accumulated other comprehensive loss (Table Amounts)
Net actuarial loss	(9,030)	(8,741)
Prior service credit	244	304
Income tax benefits related to above items	3,407	3,286
Unamortized benefit plan costs	(5,379)	(5,151)
Medical and Life Benefits
Amounts recorded in accumulated other comprehensive loss (Table Amounts)
Net actuarial loss	(113)	(220)
Prior service credit	44	66
Income tax benefits related to above items	32	64
Unamortized benefit plan costs	$ (37)	$ (90)