Condensed Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statement of Comprehensive Income [Abstract]
Unrealized gain on certain investments, tax	$ (2)	$ 1	$ (5)	$ (1)
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax Effect [Abstract]
Unrealized loss arising during period, tax	41	50	78	36
Reclassification adjustment for losses included in net earnings, tax	(12)	1	(28)	1
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	(5)	(3)	(16)	(9)
Net actuarial gains arising during the period, tax	15	(1)	(2)	(348)
Amortization of actuarial losses included in net periodic pension cost, tax	(143)	(90)	(425)	(275)
Settlements and curtailments included in net income, tax	$ 0	$ 0	$ (2)	$ (113)