Income Taxes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Income Taxes
Effective tax rate on income from continuing operations (as a percent)	21.60%	25.50%	22.20%	26.40%
Benefits tax planning and completion of audits			$ 17
Period within which capital losses must be used against capital gain income			5 years
Valuation allowance	19		19		19
Gross unrecognized tax benefit (expense)	226		226		209
Unrecognized tax benefits (net of federal tax benefits) that would impact the effective tax rate	48		48		62
Significant change in unrecognized tax benefits is reasonably possible, estimated range of change, lower bound	160		160
Significant change in unrecognized tax benefits is reasonably possible, estimated range of change, upper bound	170		170
Increase (reduction) in interest and penalties	1	2	4	4
Accrued interest and penalties	46		46		42
State and Local [Member]
Income Taxes
State net operating losses	$ 23		$ 23