Restructuring-Related Liabilities: (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2013
Current Liability
Restructuring Reserve
Liability at the beginning of the period	$ 30
Payments	(15)
Other Adjustments	14
Liability at the end of the period	29
Noncurrent Liability
Restructuring Reserve
Liability at the beginning of the period	430
Other Adjustments	(12)
Liability at the end of the period	417
Workforce | Current Liability
Restructuring Reserve
Liability at the beginning of the period	28
Payments	(15)
Other Adjustments	14
Liability at the end of the period	28
Workforce | Noncurrent Liability
Restructuring Reserve
Liability at the beginning of the period	430
Other Adjustments	(12)
Liability at the end of the period	417
Space | Current Liability
Restructuring Reserve
Liability at the beginning of the period	2
Payments	0
Other Adjustments	0
Liability at the end of the period	1
Space | Noncurrent Liability
Restructuring Reserve
Liability at the beginning of the period	0
Other Adjustments	0
Liability at the end of the period	$ 0