Employee Benefit Arrangements - Assumptions (Details) - Pension Plan	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Discount rate, benefit obligation	3.36%	4.46%
Discount rate, net benefit cost	4.37%	3.85%	4.55%
Expected rate of return on plan assets, net benefit cost	6.75%	7.50%	7.50%