Equity (Details 3) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expense	$ 56
Weighted Average Period	1 year 9 months 0 days
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expense	52
Weighted Average Period	1 year 7 months 24 days
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expense	$ 28
Weighted Average Period	1 year 8 months 27 days