Pension Benefit Plan Accountnig Methodology Changes (Details) 2 (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets		$ 1,050
Prepaid pension cost	394	368
Assets	6,706	6,371
Other current liabilities	420	407
Liabilities, Current	1,838	1,742
Liabilities	5,222	5,079
Retained earnings	1,231	1,084
Accumulated other comprehensive loss	(222)	(197)
Stockholders' Equity Attributable to Parent	1,430	1,247
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	1,468	1,277
Liabilities and Equity	6,706	6,371
Previous Accounting Guidance [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Prepaid pension cost	391
Assets	6,703
Other current liabilities	425
Liabilities, Current	1,843
Liabilities	5,227
Retained earnings	1,987
Accumulated other comprehensive loss	(986)
Stockholders' Equity Attributable to Parent	1,422
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	1,460
Liabilities and Equity	6,703
Scenario, Actual [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Prepaid pension cost	394
Assets	6,706
Other current liabilities	420
Liabilities, Current	1,838
Liabilities	5,222
Retained earnings	1,231
Accumulated other comprehensive loss	(222)
Stockholders' Equity Attributable to Parent	1,430
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	1,468
Liabilities and Equity	6,706
Previous Accounting Guidance [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings		2,134
Accumulated other comprehensive loss		(1,247)
Scenario, Actual [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings		1,084
Accumulated other comprehensive loss		$ (197)