Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Consolidated Statements of Comprehensive Income [Abstract]
Foreign currency translation adjustments, attributable to noncontrolling interest, net of taxes	$ (7)	$ 10	$ (37)	$ 6
Foreign currency translation adjustments, tax effect	(2)	74	(145)	580
Unrealized gains (losses) on available-for-sale securities - tax	(4)	28	(8)	72
Reclassification adjustment included in net income on available-for-sale securities - tax effect	0	(50)	0	(54)
Unrealized gains (losses) on cash flow hedges - tax	0	178	68	(94)
Reclassification adjustment included in net income on cash flow hedges - tax effect	3	5	9	15
Net prior service credit (cost) arising during period - tax effect	0	0	173	594
Amortization of net prior service credit included in net income, tax effect	$ (108)	$ (157)	$ (322)	$ (447)

Amount after tax and reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature, attributable to noncontrolling interests.

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