Other (income) expense (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Component of Other Income, Nonoperating [Line Items]
Other (income) expense	$ (6)	$ 81	$ (10)
Equity in net (income) loss of partially-owned entities
Component of Other Income, Nonoperating [Line Items]
Other (income) expense	(80)	(32)	(75)
Amortization of intangible assets
Component of Other Income, Nonoperating [Line Items]
Other (income) expense	51	29	9
(Gains) losses from fair value changes in seperate account assets
Component of Other Income, Nonoperating [Line Items]
Other (income) expense	(29)	36	0
Acquisition-related costs
Component of Other Income, Nonoperating [Line Items]
Other (income) expense	11	5	14
Federal excise and capital taxes
Component of Other Income, Nonoperating [Line Items]
Other (income) expense	22	20	19
Other
Component of Other Income, Nonoperating [Line Items]
Other (income) expense	$ 19	$ 23	$ 23