Benefit Plans (Funded Status) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at January 1	$ 2,943	$ 3,271
Service cost	9	12	12
Interest cost	132	121	135
Participants' contributions	0	0
Plan amendments	(3)	0
Actuarial (gain) loss	367	(289)
Benefits paid	(165)	(165)
Settlements	(257)	(8)
Foreign currency translation and other	(7)	1
Benefit obligation at December 31	3,019	2,943	3,271
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at January 1	2,656	2,425
Actual return on plan assets	216	311
Company contributions	12	92
Participants' contributions	0	0
Benefits paid	(165)	(165)
Settlements	(257)	(8)
Foreign currency translation and other	(6)	1
Fair value of plan assets at December 31	2,456	2,656	2,425
Defined Benefit Plan, Funded Status of Plan [Abstract]
Funded status	(563)	(287)
Defined Benefit Plan, Amounts Recognized in Balance Sheet [Abstract]
Other assets	9	9
Other liabilities	(572)	(296)
Net amount recognized on balance sheets	(563)	(287)
Amounts recognized in Accumulated other comprehensive income not yet recognized in net periodic cost (benefit)[Abstract]
Prior service credit	0	0
Net actuarial (gain) loss	974	745
Net amount recognized in Accumulated other comprehensive income	974	745
Other Postretirement Benefit Plan [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at January 1	40	47
Service cost	0	1	0
Interest cost	1	1	2
Participants' contributions	5	5
Plan amendments	(7)	0
Actuarial (gain) loss	1	(3)
Benefits paid	(11)	(12)
Settlements	0	0
Foreign currency translation and other	0	1
Benefit obligation at December 31	29	40	47
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at January 1	0	0
Actual return on plan assets	0	0
Company contributions	6	7
Participants' contributions	5	5
Benefits paid	(11)	(12)
Settlements	0	0
Foreign currency translation and other	0	0
Fair value of plan assets at December 31	0	0	0
Defined Benefit Plan, Funded Status of Plan [Abstract]
Funded status	(29)	(40)
Defined Benefit Plan, Amounts Recognized in Balance Sheet [Abstract]
Other assets	0	0
Other liabilities	(29)	(40)
Net amount recognized on balance sheets	(29)	(40)
Amounts recognized in Accumulated other comprehensive income not yet recognized in net periodic cost (benefit)[Abstract]
Prior service credit	(9)	(98)
Net actuarial (gain) loss	8	8
Net amount recognized in Accumulated other comprehensive income	$ (1)	$ (90)