Revenues (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Disaggregation of Revenue [Line Items]
Administration, recordkeeping and servicing fees	$ 158,991
Investment advisory and asset management fees	73,424
Other fee income	43,549
Total Fee Income	275,964	$ 255,116
Customer contract receivables	238,142
Deferred contract costs	43,999
Individual Markets
Disaggregation of Revenue [Line Items]
Administration, recordkeeping and servicing fees	1,140
Investment advisory and asset management fees	3,255
Other fee income	27,233
Total Fee Income	31,628	25,981
Empower Retirement
Disaggregation of Revenue [Line Items]
Administration, recordkeeping and servicing fees	157,851
Investment advisory and asset management fees	68,290
Other fee income	16,316
Total Fee Income	242,457	227,320
Other
Disaggregation of Revenue [Line Items]
Administration, recordkeeping and servicing fees	0
Investment advisory and asset management fees	1,879
Other fee income	0
Total Fee Income	$ 1,879	$ 1,815