Income and Other Taxes - Reconciliation of Statutory Tax Rate to Effective Tax Rate (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Income Tax Disclosure [Abstract]
U.S. federal statutory income tax rate	35.00%		35.00%		35.00%
Nondeductible expenses	1.40%		2.60%		2.00%
Effect of tax law changes	(0.60%)		0.70%		0.20%
Change in valuation allowance for deferred tax assets	0.20%		(0.70%)		(0.30%)
State taxes, net of federal benefit	2.60%		2.10%		2.40%
Audit and other tax return adjustments	(2.40%)		(4.80%)		(1.00%)
Tax-exempt income, credits and incentives	(3.80%)		(2.60%)		(3.20%)
Foreign rate differential adjusted for U.S. taxation of foreign profits(1)	(11.90%)	[1]	(12.00%)	[1]	(10.60%)	[1]
Other	0.50%		0.10%		0.10%
Effective Income Tax Rate	21.00%		20.40%		24.60%
Income Taxes Paid	$ 155		$ 137		$ 94

[1] (1)The “U.S. taxation of foreign profits” represents the U.S. tax, net of foreign tax credits, associated with actual and deemed repatriations of earnings from our non-U.S. subsidiaries.