Stockholders' Equity (Narrative) (Details) (USD $)	12 Months Ended			24 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012
Stockholders' Equity Details [Abstract]
Dividends recorded on common stock	$ 287,000,000	$ 237,000,000	$ 139,000,000
Class B Common Stock purchased, value	1,170,000,000			2,190,000,000
Average price per share repurchased (in dollars per share)	$ 32.99			$ 28.18
Class B Common Stock purchased, shares	35,500,000			77,700,000
Remaining authorization under repurchase program	$ 2,510,000,000
Minimum Class A shares needed for conversion	5,000			5,000
Conversion of A shares into B shares, in shares	300,000	200,000	8,000,000
Number of shares available for future grant under equity incentive plans	32,000,000			32,000,000