Stock Compensation Plans and Other Compensation Arrangements (Details 1) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Table Amounts]
Stock-based compensation expense	$ 183	$ 139	$ 134
Tax benefits from stock-based compensation expense	45	55	53
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Table Amounts]
Stock-based compensation expense	10	14	27
Stock awards
Share-based Compensation Arrangement by Share-based Payment Award [Table Amounts]
Stock-based compensation expense	173	125	107
Stock options, exercised
Share-based Compensation Arrangement by Share-based Payment Award [Table Amounts]
Tax benefits from stock-based compensation expense	26	18	17
Stock awards, issued
Share-based Compensation Arrangement by Share-based Payment Award [Table Amounts]
Tax benefits from stock-based compensation expense	$ 19	$ 37	$ 36