Condensed Consolidated Statements of Comprehensive Income (Parenthetical) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
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	51	6
Reclassification adjustment for losses included in net earnings, tax	(6)	(3)
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)
Net actuarial gains arising during the period, tax		(346)
Amortization of actuarial losses included in net periodic pension cost, tax	(137)	(94)
Settlements and curtailments included in net income, tax		$ (113)