Other Comprehensive Earnings (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Accumulated other comprehensive income (loss) by component
Balance at the beginning of the period	$ (1,687)		$ (1,701)
Other comprehensive (loss) income before reclassifications	13		(1)
Amounts reclassified from accumulated other comprehensive income	14		42
Other comprehensive income	27	14	41	28
Balance at the end of the period	(1,660)		(1,660)
Defined benefit plan | Pension Plans
Accumulated other comprehensive income (loss) by component
Balance at the beginning of the period	(1,372)		(1,399)
Other comprehensive (loss) income before reclassifications	0		0
Amounts reclassified from accumulated other comprehensive income	13		40
Other comprehensive income	13		40
Balance at the end of the period	(1,359)		(1,359)
Defined benefit plan | Post-Retirement Benefit Plans
Accumulated other comprehensive income (loss) by component
Balance at the beginning of the period	(288)		(289)
Other comprehensive (loss) income before reclassifications	0		0
Amounts reclassified from accumulated other comprehensive income	1		2
Other comprehensive income	1		2
Balance at the end of the period	(287)		(287)
Foreign Currency Translation Adjustment and Other
Accumulated other comprehensive income (loss) by component
Balance at the beginning of the period	(27)		(13)
Other comprehensive (loss) income before reclassifications	13		(1)
Amounts reclassified from accumulated other comprehensive income	0		0
Other comprehensive income	13		(1)
Balance at the end of the period	$ (14)		$ (14)