Income Taxes Income Tax Rate Reconciliation (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Rate Reconciliation [Line Items]
Income Tax Reconciliation, Income Tax Expense (Benefit), at Federal Statutory Income Tax Rate	$ 566	$ 956	$ 254
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate	35.00%	35.00%	35.00%
Income Tax Reconciliation, State and Local Income Taxes	20	(9)	1
Effective Income Tax Rate Reconciliation, State and Local Income Taxes	1.20%	(0.30%)	0.10%
Income Tax Reconciliation, Tax Exempt Income	80	77	72
Effective Income Tax Rate Reconciliation, Tax Exempt Income	(4.90%)	(2.80%)	(9.90%)
Effective Income Tax Rate Reconciliation, Internal Restructuring	(343)	0	0
Effective Income Tax Rate Reconciliation, Internal Restructuring Percentage	(21.30%)	0.00%	0.00%
Effective Income Tax Rate Reconciliation, Changes in UTBs, Amount	152	1	1
Effective Income Tax Rate Reconciliation, Internal Restructuring Percent	9.40%	0.00%	0.10%
Income Tax Reconciliation, Tax Credits	84	83	88
Effective Income Tax Rate Reconciliation, Tax Credits	(5.20%)	(3.00%)	(12.10%)
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Amount	49	16	6
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Percent	3.10%	0.60%	0.80%
Income Tax Reconciliation, Deductions, Dividends	1	8	14
Effective Income Tax Rate Reconciliation, Deductions, Dividends	0.00%	(0.30%)	(1.90%)
Income Tax Reconciliation, Other Adjustments	(6)	(23)	(9)
Effective Income Tax Rate Reconciliation, Other Adjustments	(0.40%)	(0.90%)	(1.20%)
Income Tax Expense (Benefit)	$ 273	$ 773	$ 79
Effective Income Tax Rate, Continuing Operations	16.90%	28.30%	10.90%