Retirement Plans (Retirement Plans, Funded Status) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Expense for the defined contribution plans for continuing operations		$ 173	$ 111	$ 288
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at end of period		1,200	1,100
Fair value of plan assets at end of period		940	865
Funded status at end of period		280	241
Amounts recognized on the Consolidated Balance Sheets
Accrued employee compensation and benefits		15	16
Employee compensation and benefits		267	227
Pension plans in which projected benefit obligation exceeded plan assets
Projected benefit obligation		1,202	1,083
Fair value of plan assets		920	840
Pension plans in which accumulated benefit obligation exceeded plan assets
Accumulated benefit obligation		1,139	1,037
Fair value of plan assets		920	840
Foreign Pension Plans, Defined Benefit
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period		940	865
Foreign Pension Plans, Defined Benefit | Cash and Cash Equivalents [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period		11	49
Foreign Pension Plans, Defined Benefit | Equity funds (b)
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period	[1],[2]	204	197
Foreign Pension Plans, Defined Benefit | Bond funds (c)
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period	[1],[3]	369	276
Foreign Pension Plans, Defined Benefit | alternatives fund [Domain]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period	[1],[4]	184	221
Foreign Pension Plans, Defined Benefit | Real Estate Funds [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period	[1],[5]	126	71
Foreign Pension Plans, Defined Benefit | Other assets
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period		46	51
Foreign Pension Plans, Defined Benefit | Level 1
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period		7	5
Foreign Pension Plans, Defined Benefit | Level 1 | Cash and Cash Equivalents [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period		0	0
Foreign Pension Plans, Defined Benefit | Level 1 | Equity funds (b)
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period	[1],[2]	0	0
Foreign Pension Plans, Defined Benefit | Level 1 | Bond funds (c)
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period	[1],[3]	0	0
Foreign Pension Plans, Defined Benefit | Level 1 | alternatives fund [Domain]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period	[1],[4]	0	0
Foreign Pension Plans, Defined Benefit | Level 1 | Real Estate Funds [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period	[1],[5]	0	0
Foreign Pension Plans, Defined Benefit | Level 1 | Other assets
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period		7	5
Foreign Pension Plans, Defined Benefit | Level 2
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period		842	755
Foreign Pension Plans, Defined Benefit | Level 2 | Cash and Cash Equivalents [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period		11	49
Foreign Pension Plans, Defined Benefit | Level 2 | Equity funds (b)
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period	[1],[2]	204	197
Foreign Pension Plans, Defined Benefit | Level 2 | Bond funds (c)
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period	[1],[3]	323	232
Foreign Pension Plans, Defined Benefit | Level 2 | alternatives fund [Domain]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period	[1],[4]	184	221
Foreign Pension Plans, Defined Benefit | Level 2 | Real Estate Funds [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period	[1],[5]	98	36
Foreign Pension Plans, Defined Benefit | Level 2 | Other assets
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period		22	20
Foreign Pension Plans, Defined Benefit | Level 3
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period		91	105
Foreign Pension Plans, Defined Benefit | Level 3 | Cash and Cash Equivalents [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period		0	0
Foreign Pension Plans, Defined Benefit | Level 3 | Equity funds (b)
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period	[1],[2]	0	0
Foreign Pension Plans, Defined Benefit | Level 3 | Bond funds (c)
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period	[1],[3]	46	44
Foreign Pension Plans, Defined Benefit | Level 3 | alternatives fund [Domain]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period	[1],[4]	0	0
Foreign Pension Plans, Defined Benefit | Level 3 | Real Estate Funds [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period	[1],[5]	28	35
Foreign Pension Plans, Defined Benefit | Level 3 | Other assets
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Fair value of plan assets at end of period		$ 17	$ 26
United Kingdom Pension Plan
Pension plans in which accumulated benefit obligation exceeded plan assets
United Kingdom pension plan percentage of international pension plans' projected benefit obligations		84.00%

[1] Common/collective trust funds are valued at the net asset value of units held by the plans at year-end.

[2] Strategy is to invest in diversified funds of global common stocks.

[3] Strategy is to invest in diversified funds of fixed income securities of varying geographies and credit quality and whose cash flows approximate the maturities of the benefit obligation.

[4] Strategy is to invest in a fund of diversifying investments, including but not limited to reinsurance, commodities and currencies.

[5] Strategy is to invest in diversified funds of real estate investment trusts and private real estate.