Income Taxes Level 4 Capital Loss Carryover (Details) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Tax Credit Carryforwards, General Business	$ 90	$ 99
Tax Credit Carryforward, Amount	0	0
Deferred Tax Assets, Capital Loss Carryforwards	0	$ 0
Expiring Tax Year 2031 to 2036 [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Tax Credit Carryforwards, General Business	90
Expiring Tax Year 2019 [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Capital Loss Carryforwards	$ 0