Income Taxes Level 4 Effective Income Tax Rate Reconciliation (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount		$ 282	$ 692	$ 595
Effective Income Tax Rate Reconciliation, Tax Exempt Income, Amount		124	132	138
Effective Income Tax Rate Reconciliation, Deduction, Dividends, Amount		82	156	114
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount		(79)	(102)	5
Effective Income Tax Rate Reconciliation, Tax Credit, Investment, Amount		(79)	0	0
Effective Income Tax Rate Reconciliation, Disposition of Business, Amount		(37)	0	0
Effective Income Tax Rate Reconciliation, Other Adjustments, Amount		(27)	(3)	(2)
Income Tax Expense (Benefit)		(92)	$ 305	$ 350
Solar Investment Realized Loss		113
HFPI estimated tax benefit on disposition	$ 0
Internal Revenue Service (IRS) [Member]
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Effective Income Tax Rate Reconciliation, Other Adjustments, Amount		$ 33