Employee Benefits - Schedule of changes in level 3 fair value for Other Plans (Details) (Other [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013
Change in fair value of plan assets
Balance at the beginning of the period	$ 1,061		$ 1,009
Actual return on plan assets:
Foreign currency impact	(128)		7
Balance at the end of the period	1,161		1,061
Pooled funds - Real estate [Member]
Actual return on plan assets:
Balance at the end of the period			17	[1],[2]
Alternative investments [Member]
Actual return on plan assets:
Balance at the end of the period	8	[1],[3]	8	[1],[3]
Significant Unobservable Inputs (Level 3) [Member]
Change in fair value of plan assets
Balance at the beginning of the period	25		28
Actual return on plan assets:
Relating to assets still held at the end of the year	1		0
Relating to assets sold during the year	0		1
Purchases, sales and settlements—net	(17)		(4)
Transfer in/(out) of Level 3	0		0
Foreign currency impact	(1)		0
Balance at the end of the period	8		25
Significant Unobservable Inputs (Level 3) [Member] | Pooled funds - Real estate [Member]
Change in fair value of plan assets
Balance at the beginning of the period	17	[1],[2]	17
Actual return on plan assets:
Relating to assets still held at the end of the year	0		(1)
Relating to assets sold during the year	0		0
Purchases, sales and settlements—net	(17)		0
Transfer in/(out) of Level 3	0		0
Foreign currency impact	0		1
Balance at the end of the period	0		17	[1],[2]
Significant Unobservable Inputs (Level 3) [Member] | Alternative investments [Member]
Change in fair value of plan assets
Balance at the beginning of the period	8	[1],[3]	11
Actual return on plan assets:
Relating to assets still held at the end of the year	1		1
Relating to assets sold during the year	0		1
Purchases, sales and settlements—net	0		(4)
Transfer in/(out) of Level 3	0		0
Foreign currency impact	(1)		(1)
Balance at the end of the period	$ 8	[1],[3]	$ 8	[1],[3]

[1] Consists of various equity, fixed income, commodity, and real estate mutual fund type investment vehicles.

[2] Consists of property funds and trusts holding direct real estate investments.

[3] Consists of limited partnerships, private equity and hedge funds.