Consolidated Statements of Comprehensive Income Parenthetical (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Tax on foreign currency translation	$ 0	$ 0	$ 1
Defined benefit plans:
Tax on amortization of prior service cost and unrecognized gains and losses included in total benefit cost	9	8	6
Tax on increase in net actuarial losses	(54)	(26)	(23)
Tax on immediate recognition of prior service cost and unrecognized gains and losses due to curtailments, settlements, and divestitures	1	1	4
Tax on prior service credit (cost) from plan amendments	3	0	0
Tax on deferred derivative gains (losses)	0	1	0
Tax on reclassification adjustment for amounts recognized in income	(3)	2	0
Tax on unrealized investment gains	$ 0	$ 0	$ 0