Variable Annuity and Insurance Guarantees (VA Guarantees Details) (Details) - USD ($) $ in Millions		9 Months Ended	12 Months Ended
		Sep. 30, 2018	Dec. 31, 2017
GMDB [Member]
Variable Annuity Guarantees by Benefit Type
Total contract value	[1]	$ 78,695	$ 79,498
Contract value in separate accounts	[1]	73,609	74,378
Net amount at risk	[1]	$ 106	$ 83
Weighted average attained age	[1]	67 years	66 years
GMDB [Member] | Return of premium [Member]
Variable Annuity Guarantees by Benefit Type
Total contract value	[1]	$ 61,379	$ 61,418
Contract value in separate accounts	[1]	59,441	59,461
Net amount at risk	[1]	$ 12	$ 9
Weighted average attained age	[1]	67 years	66 years
GMDB [Member] | Five/six-year reset [Member]
Variable Annuity Guarantees by Benefit Type
Total contract value	[1]	$ 8,504	$ 8,870
Contract value in separate accounts	[1]	5,781	6,149
Net amount at risk	[1]	$ 11	$ 12
Weighted average attained age	[1]	66 years	66 years
GMDB [Member] | One-year ratchet [Member]
Variable Annuity Guarantees by Benefit Type
Total contract value	[1]	$ 6,215	$ 6,548
Contract value in separate accounts	[1]	5,864	6,187
Net amount at risk	[1]	$ 19	$ 11
Weighted average attained age	[1]	69 years	69 years
GMDB [Member] | Five-year ratchet [Member]
Variable Annuity Guarantees by Benefit Type
Total contract value	[1]	$ 1,471	$ 1,563
Contract value in separate accounts	[1]	1,416	1,506
Net amount at risk	[1]	$ 1	$ 1
Weighted average attained age	[1]	65 years	65 years
GMDB [Member] | Other [Member]
Variable Annuity Guarantees by Benefit Type
Total contract value	[1]	$ 1,126	$ 1,099
Contract value in separate accounts	[1]	1,107	1,075
Net amount at risk	[1]	$ 63	$ 50
Weighted average attained age	[1]	72 years	72 years
GGU death benefit [Member]
Variable Annuity Guarantees by Benefit Type
Total contract value	[1]	$ 1,105	$ 1,118
Contract value in separate accounts	[1]	1,055	1,067
Net amount at risk	[1]	$ 129	$ 133
Weighted average attained age	[1]	70 years	70 years
GMIB [Member]
Variable Annuity Guarantees by Benefit Type
Total contract value	[1]	$ 208	$ 233
Contract value in separate accounts	[1]	192	216
Net amount at risk	[1]	$ 7	$ 7
Weighted average attained age	[1]	69 years	69 years
GMWB [Member]
Variable Annuity Guarantees by Benefit Type
Total contract value	[1]	$ 47,123	$ 46,883
Contract value in separate accounts	[1]	47,021	46,759
Net amount at risk	[1]	$ 218	$ 130
Weighted average attained age	[1]	68 years	67 years
GMWB [Member] | GMWB standard benefit [Member]
Variable Annuity Guarantees by Benefit Type
Total contract value	[1]	$ 2,252	$ 2,508
Contract value in separate accounts	[1]	2,245	2,500
Net amount at risk	[1]	$ 1	$ 1
Weighted average attained age	[1]	72 years	71 years
GMWB [Member] | GMWB for life [Member]
Variable Annuity Guarantees by Benefit Type
Total contract value	[1]	$ 44,871	$ 44,375
Contract value in separate accounts	[1]	44,776	44,259
Net amount at risk	[1]	$ 217	$ 129
Weighted average attained age	[1]	68 years	67 years
GMAB [Member]
Variable Annuity Guarantees by Benefit Type
Total contract value	[1]	$ 2,762	$ 3,086
Contract value in separate accounts	[1]	2,758	3,083
Net amount at risk	[1]	$ 0	$ 0
Weighted average attained age	[1]	59 years	59 years

[1] Individual variable annuity contracts may have more than one guarantee and therefore may be included in more than one benefit type. Variable annuity contracts for which the death benefit equals the account value are not shown in this table.