Benefit Plans (Funded Status) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Funded Status of Plan
Funded status	$ (791)	$ (540)
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Funded Status of Plan
Funded status	(49)	(95)
Change in Benefit Obligation [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Funded Status of Plan
Benefit obligation at January 1	2,798	2,702
Service cost	13	16
Interest cost	146	149
Participants' contributions
Plan amendments
Actuarial (gain) loss	263	89
Benefits paid	(163)	(157)
Foreign currency translation and other on benefit obligation		(1)
Reduction of benefit obligation due to disposition of subsidiary	(54)
Benefit obligation at December 31	3,003	2,798
Change in Benefit Obligation [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Funded Status of Plan
Benefit obligation at January 1	95	155
Service cost	1	1
Interest cost	3	7
Participants' contributions	6	6
Plan amendments	(12)	(60)
Actuarial (gain) loss	(18)	(2)
Benefits paid	(13)	(13)
Foreign currency translation and other on benefit obligation		1
Reduction of benefit obligation due to disposition of subsidiary	(13)
Benefit obligation at December 31	49	95
Change in plan assets [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Funded Status of Plan
Fair value of plan assets at January 1	2,258	2,117
Actual return on plan assets	82	234
Company contributions	89	65
Participants' contributions
Benefits paid	163	157
Foreign currency translation and other on plan assets		(1)
Reduction of plan assets due to disposition of subsidiary	(54)
Fair value of plan assets at December 31	2,212	2,258
Change in plan assets [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Funded Status of Plan
Fair value of plan assets at January 1
Actual return on plan assets
Company contributions	7	7
Participants' contributions	(6)	(6)
Benefits paid	13	13
Foreign currency translation and other on plan assets
Reduction of plan assets due to disposition of subsidiary
Fair value of plan assets at December 31
Amounts Recognized on the Consolidated Balance Sheets [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Funded Status of Plan
Other assets	1	7
Other liabilities	(792)	(547)
Net amount recognized on balance sheets	(791)	(540)
Amounts Recognized on the Consolidated Balance Sheets [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Funded Status of Plan
Other assets
Other liabilities	(49)	(95)
Net amount recognized on balance sheets	(49)	(95)
Amounts Recognized in Accumulated Other Comprehensive Income [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Funded Status of Plan
Prior service cost (credit)
Net actuarial (gain) loss	1,060	741
Net amount recognized in Accumulated other comprehensive income	1,060	741
Amounts Recognized in Accumulated Other Comprehensive Income [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Funded Status of Plan
Prior service cost (credit)	(134)	(141)
Net actuarial (gain) loss	9	29
Net amount recognized in Accumulated other comprehensive income	$ (125)	$ (112)