Segment Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($) segment	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Financial information of the segments
Number of Reportable Segments | segment	3
Revenue:
Premium income	$ 439,731	$ 465,349	$ 445,550
Fee income	1,060,122	956,817	944,526
Other revenue	9,611	12,261	13,563
Net investment income	1,220,053	1,276,559	1,254,430
Realized investments gains (losses), net	46,403	92,882	83,710
Total revenues	2,775,920	2,803,868	2,741,779
Benefits and expenses:
Policyholder benefits	1,241,134	1,241,023	1,234,627
Operating expenses	1,248,284	1,246,241	1,218,173
Total benefits and expenses	2,489,418	2,487,264	2,452,800
Income before income taxes	286,502	316,604	288,979
Income tax expense (benefit)	(82,614)	85,512	98,524
Net income	369,116	231,092	190,455
Assets:
Investments	32,137,282	30,600,850
Other assets	2,647,314	2,652,531
Separate account assets	27,660,571	27,037,765
Total assets	62,461,262	60,308,798
Continuing Operations
Assets:
Total assets	62,445,167	60,291,146
Discontinued Operations
Assets:
Total assets	16,095	17,652
Individual Markets Segment
Revenue:
Premium income	357,244	379,127	360,783
Fee income	110,128	99,514	87,471
Other revenue	0	0	0
Net investment income	738,002	798,557	801,935
Realized investments gains (losses), net	32,652	40,899	28,864
Total revenues	1,238,026	1,318,097	1,279,053
Benefits and expenses:
Policyholder benefits	953,371	969,182	931,631
Operating expenses	169,234	175,016	159,719
Total benefits and expenses	1,122,605	1,144,198	1,091,350
Income before income taxes	115,421	173,899	187,703
Income tax expense (benefit)	38,605	58,601	64,360
Net income	76,816	115,298	123,343
Assets:
Investments	17,791,097	16,770,772
Other assets	1,465,544	1,453,717
Separate account assets	8,494,248	7,521,475
Individual Markets Segment | Continuing Operations
Assets:
Total assets	27,750,889	25,745,964
Empower Retirement Segment
Revenue:
Premium income	2,172	1,853	533
Fee income	943,038	851,620	853,076
Other revenue	9,611	12,261	13,563
Net investment income	434,677	428,327	398,639
Realized investments gains (losses), net	13,752	51,209	54,752
Total revenues	1,403,250	1,345,270	1,320,563
Benefits and expenses:
Policyholder benefits	206,544	206,143	201,791
Operating expenses	998,431	1,002,129	992,564
Total benefits and expenses	1,204,975	1,208,272	1,194,355
Income before income taxes	198,275	136,998	126,208
Income tax expense (benefit)	64,252	25,144	43,058
Net income	134,023	111,854	83,150
Assets:
Investments	12,472,906	12,195,748
Other assets	1,027,458	1,057,148
Separate account assets	19,166,323	19,516,290
Empower Retirement Segment | Continuing Operations
Assets:
Total assets	32,666,687	32,769,186
Other Segment
Revenue:
Premium income	80,315	84,369	84,234
Fee income	6,956	5,683	3,979
Other revenue	0	0	0
Net investment income	47,374	49,675	53,856
Realized investments gains (losses), net	(1)	774	94
Total revenues	134,644	140,501	142,163
Benefits and expenses:
Policyholder benefits	81,219	65,698	101,205
Operating expenses	80,619	69,096	65,890
Total benefits and expenses	161,838	134,794	167,095
Income before income taxes	(27,194)	5,707	(24,932)
Income tax expense (benefit)	(185,471)	1,767	(8,894)
Net income	158,277	3,940	$ (16,038)
Assets:
Investments	1,873,279	1,634,330
Other assets	154,312	141,666
Separate account assets	0	0
Other Segment | Continuing Operations
Assets:
Total assets	$ 2,027,591	$ 1,775,996