Pension Plans and Other Postretirement Benefits (Tables)

3 Months Ended

Mar. 31, 2013

Table Text Block [Abstract]

Components of Net Periodic Benefit Cost Table

	Pension Benefits				Other Benefits
millions	2013		2012		2013		2012
Three Months Ended March 31
Service cost	$	21	$	19	$	2	$	2
Interest cost		20		21		4		4
Expected return on plan assets		(23)		(23)		—		—
Amortization of net actuarial loss (gain)		29		23		—		—
Net periodic benefit cost	$	47	$	40	$	6	$	6