Additional Financial Information (Restructuring Costs) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Restructuring Reserve [Roll Forward]
Balance, beginning of period				$ 32				$ 0	$ 32	$ 0
Personnel related restructuring										50
Nonpersonnel related restructuring										35
Restructuring costs	0	0	23	31	(5)	36	48	6	54	85	0
Cash payments									(64)	(53)
Balance, end of period	22				32				22	32	0
2013 Restructuring Program [Member]
Restructuring Reserve [Roll Forward]
Balance, beginning of period				0				0	0	0
Personnel related restructuring										0
Nonpersonnel related restructuring										0
Restructuring costs									54
Cash payments									(54)	0
Balance, end of period	0				0				0	0
2012 Restructuring Program [Member]
Restructuring Reserve [Roll Forward]
Balance, beginning of period				32				0	32	0
Personnel related restructuring										50
Nonpersonnel related restructuring										35
Restructuring costs									0
Cash payments									(10)	(53)
Balance, end of period	$ 22				$ 32				$ 22	$ 32