Retirement Plans (Amounts Recognized On The Consolidated Balance Sheet) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Current liabilities	$ (318)	$ (275)
Noncurrent liabilities	(5,671)	(4,627)
Pension Benefits
Noncurrent assets	144	110
Current liabilities	(114)	(90)
Noncurrent liabilities	(4,917)	(4,012)
Net liability recognized	(4,887)	(3,992)
Other Postretirement Benefit Plans, Defined Benefit
Noncurrent assets	0	0
Current liabilities	(204)	(185)
Noncurrent liabilities	(754)	(615)
Net liability recognized	$ (958)	$ (800)