Fair value measurements Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2017		Mar. 31, 2016		Dec. 31, 2015
Guaranteed Minimum Income Benefit [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Reported liabilities				$ 1,100		$ 888
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance - Beginning of Period, Liabilities		$ 559	[1]	609	[2]
Transfers into level 3, liability		0		0
Transfers out of Level 3, Liabilities		0		0
Change in Net Unrealized Gains (Losses) included in OCI, Liabilities		0		0
Net Realized Gains/Losses, Liabilities		(93)		230	[2]
Purchases, Liabilities		0		0
Sales, Liabilities		0		0
Settlements, Liabilities		0		0
Balance - End of Period, Liabilities	[1]	466		839	[2]
Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss)		(93)		230
Guaranteed Minimum Income Benefit [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance - Beginning of Period, Liabilities		559
Other Derivative Instruments Fair Value [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance - Beginning of Period, Liabilities		13		6
Transfers into level 3, liability		0		0
Transfers out of Level 3, Liabilities		0
Change in Net Unrealized Gains (Losses) included in OCI, Liabilities		0		0
Net Realized Gains/Losses, Liabilities		(2)		2
Purchases, Liabilities		0		2
Sales, Liabilities		0		0
Settlements, Liabilities		0		0
Balance - End of Period, Liabilities		11		10
Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss)		$ (2)		$ 2

[1] Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets. The liability for GLB reinsurance was $774 million at March 31, 2017, and $853 million at December 31, 2016, which includes a fair value derivative adjustment of $466 million and $559 million, respectively.

[2] Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets. The liability for GLB reinsurance was $1.1 billion at March 31, 2016, and $888 million at December 31, 2015, which includes a fair value derivative adjustment of $839 million and $609 million, respectively.(2) Includes acquired invested assets as a result of the Chubb Corp acquisition.