Condensed Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Statement of Comprehensive Income [Abstract]
Unrealized gain on certain investments, tax	$ (1)	$ 1
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax Effect [Abstract]
Unrealized loss arising during period, tax	(28)	(32)
Reclassification adjustment for losses included in net earnings, tax	(9)	(12)
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Tax, Portion Attributable to Parent [Abstract]
Amortization of prior service cost included in net periodic pension cost, tax	16	7
Net actuarial gains arising during the period, tax	(1)	181
Amortization of actuarial losses included in net periodic pension cost, tax	(72)	(72)
Settlements and curtailments included in net income, tax		(6)
Pension and post retirement benefits related to our equity method investments, tax	$ 1	$ (4)