Benefit Plans (Funded Status) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan, Amounts Recognized in Balance Sheet [Abstract]
Defined Benefit Plan, Assets for Plan Benefits	$ 2,193	$ 2,267
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at January 1	2,821	3,019
Service cost	0	4	$ 9
Interest cost	113	112	132
Participants' contributions	0	0
Plan amendments	0	(55)
Actuarial (gain) loss	68	(79)
Benefits paid	(173)	(173)
Foreign currency translation and other	(14)	(7)
Decrease in Benefit Obligation due to settlement	(86)	0
Benefit obligation at December 31	2,729	2,821	3,019
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at January 1	2,267	2,456
Actual return on plan assets	193	(18)
Company contributions	9	10
Participants' contributions	0	0
Benefits paid	(173)	(173)
Foreign currency translation and other	(15)	(8)
Settlement through group annuity purchase	(88)	0
Fair value of plan assets at December 31	2,193	2,267	2,456
Defined Benefit Plan, Funded Status of Plan [Abstract]
Funded status	(536)	(554)
Defined Benefit Plan, Amounts Recognized in Balance Sheet [Abstract]
Defined Benefit Plan, Assets for Plan Benefits	4	12
Other liabilities	(540)	(566)
Net amount recognized on balance sheets	(536)	(554)
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	999	999
Net amount recognized in Accumulated other comprehensive income	999	999
Other Postretirement Benefit Plan [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at January 1	23	29
Service cost	0	0
Interest cost	0	1	1
Participants' contributions	4	4
Plan amendments	0	0
Actuarial (gain) loss	(6)	(3)
Benefits paid	(7)	(8)
Foreign currency translation and other	1	0
Decrease in Benefit Obligation due to settlement	0	0
Benefit obligation at December 31	15	23	29
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	3	4
Participants' contributions	4	4
Benefits paid	(7)	(8)
Foreign currency translation and other	0	0
Settlement through group annuity purchase	0	0
Fair value of plan assets at December 31	0	0	$ 0
Defined Benefit Plan, Funded Status of Plan [Abstract]
Funded status	(15)	(23)
Defined Benefit Plan, Amounts Recognized in Balance Sheet [Abstract]
Defined Benefit Plan, Assets for Plan Benefits	0	0
Other liabilities	(15)	(23)
Net amount recognized on balance sheets	(15)	(23)
Amounts recognized in Accumulated other comprehensive income not yet recognized in net periodic cost (benefit)[Abstract]
Prior service credit	(4)	(6)
Net actuarial (gain) loss	(3)	3
Net amount recognized in Accumulated other comprehensive income	$ (7)	$ (3)