Income Taxes Level 4 Effective Income Tax Rate Reconciliation (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Income Tax Contingency [Line Items]
Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount	$ 219	$ 213
Effective Income Tax Rate Reconciliation, Tax Exempt Income, Amount	34	35
Effective Income Tax Rate Reconciliation, Deduction, Dividends, Amount	23	27
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount	(1)	0
Effective Income Tax Rate Reconciliation, Other Adjustments, Amount	(3)	(8)
Income Tax Expense (Benefit)	$ 158	$ 143