Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Comprehensive Income [Abstract]
Unrealized gain on certain investments, tax	$ (5)	$ 0	$ 0
Unrealized (loss)/gain on derivative instruments:
Unrealized loss arising during period, tax	77	77	42
Reclassification adjustment for loss/(gain) included in net earnings, tax	(43)	(4)	9
Defined benefit pension plans & other postretirement benefits:
Net actuarial gain/(loss) arising during the period, tax	402	2,588	(3,437)
Amortization of actuarial losses included in net periodic pension cost, tax	(570)	(367)	(849)
Settlements and curtailments included in net income, tax	(27)	(101)	(33)
Pension and post retirement benefits related to our equity method investments, tax	(2)	15	(13)
Amortization of prior service cost included in net periodic pension cost, tax	(22)	(12)	(6)
Prior service cost arising during the period, tax	$ (496)	$ 3	$ 41