Share-Based Compensation Plans Employee Share Purchase Plan Narrative (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	$ 300	$ 212	$ 235
United States [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Period of interval for purchase of common stock			6 months	3 months
Purchase price expressed as a percentage of the fair market value of common stock			85.00%	85.00%
Stock issued to employees under the plan (in shares)	556,000	621,000	468,000
Total share-based compensation expense	6	6	5
United States [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Purchase of shares under plan	7,500,000
United Kingdom [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Purchase of shares under plan	350,000			300,000
Stock issued to employees under the plan (in shares)	172,000	25,000	63,000
Waiting period before purchase of shares	3 years
Total share-based compensation expense	$ 1	$ 1	$ 1