Insurance (Guarantees Related to Annuity Contracts) (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Variable Annuity Guarantees: | Guaranteed Death Benefits
Net Amount at Risk by Product and Guarantee [Line Items]
Total account value	$ 180,789	$ 181,413
Separate account value	151,174	151,901
Net amount at risk	$ 9,916	$ 10,339
Average attained age of contractholders	66 years	66 years
Variable Annuity Guarantees: | Guaranteed Annuitization Benefits
Net Amount at Risk by Product and Guarantee [Line Items]
Total account value	$ 91,042	$ 91,240
Separate account value	87,414	87,841
Net amount at risk	$ 4,150	$ 2,762
Average attained age of contractholders	66 years	66 years
Other Annuity Guarantees: | Guaranteed Annuitization Benefits
Net Amount at Risk by Product and Guarantee [Line Items]
Total account value	$ 1,514	$ 1,560
Net amount at risk	$ 401	$ 422
Average attained age of contractholders	51 years	51 years