Consolidated Statements of Shareholders' Equity Parenthetical - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Tax on foreign currency translation	$ (52)	$ (46)	$ 0
Tax on foreign currency translation reclassification adjustment recognized in income	0	0	0
Tax on amortization of prior service cost and unrecognized gains and losses included in total benefit cost	34	36	10
Tax on decrease (increase) in net actuarial losses	(19)	(135)	34
Tax on immediate recognition of prior service cost and unrecognized gains and losses due to curtailments, settlements, and divestitures	67	13	1
Tax on prior service credit from plan amendments	0	0	0
Tax on deferred derivative gains	3	1	1
Tax on reclassification adjustment for amounts recognized in income	(3)	(1)	0
Tax on unrealized investment gains	(2)	1	0
Tax on unrealized investment gains reclassification adjustment recognized in income	$ 2	$ 0	$ 0
Total Shareholders' Equity
Common treasury stock (shares)	11,445,445	8,979,927	3,136,663	5,648,930
Tax on foreign currency translation	$ (52)	$ (46)	$ 0
Tax on foreign currency translation reclassification adjustment recognized in income	0	0	0
Tax on amortization of prior service cost and unrecognized gains and losses included in total benefit cost	34	36	9
Tax on decrease (increase) in net actuarial losses	(19)	(129)	33
Tax on immediate recognition of prior service cost and unrecognized gains and losses due to curtailments, settlements, and divestitures	67	13	1
Tax on prior service credit from plan amendments			0
Tax on deferred derivative gains	3	1	1
Tax on reclassification adjustment for amounts recognized in income	(3)		0
Tax on unrealized investment gains	(2)	$ 1	$ 0
Tax on unrealized investment gains reclassification adjustment recognized in income	2
Tax on deconsolidation of subsidiary	$ 0